Picture the scene: just two hours remained before Jimmy Carter was to relinquish the presidency to Ronald Reagan. A kind of gallows humor gripped the weary officials in the Oval Office of the White House as it became clear that the Iranian hostages were still stuck on the ground in Tehran.

Outgoing Vice President Walter Mondale turned to outgoing Secretary of State Edmund Muskie and said, "Ed, you know when you'll first realize that you're out of power? It's when you have to take the goddam Eastern Shuttle to New York instead of an Air Force jet."

For 20 years, the Eastern Shuttle, one of the great innovations in the history of commercial aviation, has been flying from National and La Guardia Airports, every hour on the hour, from early morning to late at night, seven days a week, linking New York and Washington. (Eastern also offers Shuttle service between La Guardia and Logan Airport in Boston).

The planes may be Boeing 727s, but the ambience is that of a Metrobus in the sky. There are no drinks, no sandwiches, no first-class seating, no amenities. Passengers, squeezed three abreast in the 177 seats, routinely describe the Shuttle as "a cattle car." They may complain and curse, but passenger loyalty to the no-frills service remains high. Eastern carries 800,000 people a year between Washington and New York with peak daily loads of 4,000 common over the Thanksgiving weekend.

Eastern is selling one precious commodity--convenience--in exchange for its $59 one-way weekday fare. No reservations are needed on the 96 flights per week and harried travelers can buy a ticket on board, with American Express cards the most common form of payment. If a Shuttle flight is full, Eastern says it will provide a backup plane to guarantee seating.

These backup planes are what make the Shuttle unique in North America. (British Airways, which came to Eastern for assistance, now provides similar service between London and other major English cities). During the 1960s, when Eastern flew smaller planes, there were about 50 occasions when the Shuttle provided a backup flight for a single passenger. This expensive gesture hasn't been duplicated in a decade, but Eastern was flying about 60 backup flights a week prior to the air traffic controllers' strike. The Shuttle is still flying its regular schedule, but Eastern says air traffic congestion at La Guardia limits them to about five backup flights a day.

Thanks to airline deregulation, there is now a cheaper and often more pleas ant way to make the 210-mile trip between Washington and New York. Since late last year, New York Air, an aggressive affiliate of Texas International Airlines, has been flying the same route 14 times a day, offering reservations, free drinks and a cut-rate regular fare of $49. (In addition, there are a few flights per day between National and La Guardia on other airlines such as Braniff and Pan Am).

The new competition from New York Air may have made the Shuttle stewardesses a bit more friendly, but Eastern stoutly maintains that passenger loads have remained constant throughout 1981. Officials of both airlines say that New York Air has stimulated the market by attracting new passengers rather than taking business away from the Shuttle. Although New York Air carried 200,000 passengers on the Washington-New York route during its first nine months of operation, business travelers still seem to prefer the guaranteed seat on the Shuttle to a free bloody mary.

According to Eastern's last passenger survey in early 1980, 80 percent of weekday Shuttle passengers are traveling on business--a euphemistic way of saying that someone else is footing the bill. Shuttleites are disproportionately male with a median age of 40. Three- fourths of them are classified as executives, professionals or managers. Two- thirds of the Shuttle passengers had family incomes in excess of $40,000 per year in 1980, and half of them were living on more than $50,000.

Have you ever been seated in a fancy restaurant and started wondering what all the other button-down types brandishing their American Express Gold Cards did for a living? A few months ago I began having the same voyeuristic curiosity about my fellow Shuttle passengers. I wasn't writing a story or taking notes, just chatting idly with my seatmates as I was scrunched in a middle seat on an early morning flight to New York.

On my left was a Washington-based tax attorney who claimed to spend 250 days a year on the road advising corporate clients how to legally avoid paying too much tribute to the Internal Revenue Service. On my right was a woman from Potomac who described herself as the promotions director for major league baseball. Despite the then-raging baseball strike, she was en route to the Big Apple to arrange for a late fall celebrity "roast" of Billy Martin to be televised as a network special.

I began to realize that it was possible nobody on the entire aircraft did anything tangible for a living. Despite lagging American productivity, none of my fellow passengers were building steel mills or selling diesel engines. Instead, they were all interfacing, interacting, consulting, coordinating, advising and arranging.

I had long been curious about the relationship between New York and Washington. You know the popular images: New York has money, sophistication, two baseball teams and great pastrami sandwiches; Washington has power, a cultural inferiority complex, lousy bagels and control of nuclear weapons.

But I had grown tired of clich,es. I wanted to know why almost a million people Shuttle between Washington and New York each year. Sure most of them were traveling on business, but that bland description covers a multitude of sins.

A small sociological experiment was in order. With the permission of Eastern Airlines, I randomly selected a late afternoon Shuttle flight from La Guardia as my laboratory. It was, as expected, largely filled with weary Washingtonians who had spent the day taking care of business in New York.

Buttonholing travelers in the Shuttle waiting room and roaming the aisle once on board, I collected business cards and asked these daytrippers to explain why this trip was necessary.

Here's what I discovered:

It's 5:45 on a sticky Tuesday summer afternoon. The first section of the 5 o'clock Shuttle from La Guardia is still on the tarmac. The heat inside the plane makes one dream of the comfort of a Greyhound bus. Silk ties have been loosened, seat belts have been unbuckled and leather monogrammed attach,e cases have been opened. One can sense the collective longing for a scotch and soda. Welcome to life in the fast lane.

Even on the no-frills Shuttle, where all seats are assigned on a first-come basis, there is a social pecking order. Like prisoners who dream of stealing an extra helping of gruel, experienced Shuttleites covet the two front row seats on the right. The first row means extra leg room and the presence of a bulkhead on the right eliminates the hated middle seat. Out of such scant comforts, class distinctions emerge.

Let's start with these bulkhead seats and work backwards, row-by-row, meeting some of our fellow passengers. Socialites

The bulkhead seats belong to a Washington couple who take their luxuries seriously. Maurice Tobin is a Washington lawyer who is also the chairman of the board of the National Theatre. His wife, Joan, is, among other things, an heir to the Fleischmann margarine fortune. They arrived at La Guardia in time to snag two of the last seats on the 4 p.m. Shuttle. But middle seats in the back of the plane aren't their style. Better to wait an hour at the front of the line for the honor of sitting in the bulkhead seats on the 5 o'clock flight.

"We're on the Shuttle once a week," said Maurice Tobin. "We always see people we know. It's like a continuation of a Washington cocktail party. It's like you're in a drawing room without any of the amenities."

Joan Tobin, who has her own firm in the trendy venture capital game, spent part of the day on Wall Street working on an oil venture. Then it was uptown for business meetings with the pricy auction house of Sotheby Parke Bernet. These meetings have become almost a weekly ritual since Tobin became head of Sotheby's new Washington office last year. It was a hectic time for Tobin because she was getting ready to attend one of those luxurious, yet cerebral, two-week executive seminars run by the Aspen Institute in Colorado.

Meanwhile, Maurice Tobin was in New York's theatrical district meeting with the Shubert organization to plan the final arrangements for the National Theatre's premiere of the hit musical Evita. Among the major issues resolved this morning was a tentative decision to erect a tent in the new park opposite the National Theatre for the opening night festivities.

If venture capital is the rage among millionaires, then mergers and acquisitions are the hot tickets among lawyers. On a day when Joan Tobin worked to create a new oil venture on Wall Street, her husband spent the afternoon on Park Avenue with fellow lawyers discussing the fate of an Oklahoma energy firm he preferred not to identify that was about to be gobbled up by a merger. Adviser

Seated across the aisle from the Tobins, Leon Podolsky, a retired consulting engineer from Pittsfield, Mass., spent most of the flight reading The Wall Street Journal. Podolsky was headed to Washington for a Wednesday meeting at the Commerce Department of one of those government advisory committees that Jimmy Carter failed to abolish.

Podolsky sits on the Industry Functional Advisory Committee on Standards. This group, according to its charter, is designed to help American negotiators eliminate foreign engineering and electrical standards that are barriers to international trade. Speech Student

The left window seat in the second row belonged to E. E. Dudenhoeffer, a manager with IBM's data processing division in Bethesda. Discovering that he was returning from a two-day business trip to New York for one of America's industrial giants, I was all set to conclude that here, at last, was a man doing something productive.

Wrong. IBM had paid the freight for Dudenhoeffer to attend a two-day course in public speaking run by a Manhattan firm called Communispond. "I learned how to control an audience through eye contact," he explained. "They taught me how to use my mannerisms to the best advantage. I know it sounds corny, but that's how it works."

Dudenhoeffer was appalled that the course cost IBM $750 plus his travel and hotel bills. "That's a hell of a lot of money for two days," he said. "I can send a kid to Montgomery Community College for a whole year for that." Apartment Hunter

Jammed in the middle seat in the second row, Janice M. Johnson was savoring a major life victory. She had found an affordable one-bedroom apartment in Manhattan, opposite Lincoln Center. By Washington standards the $800-per-month tariff was steep, but compared to the $1,200-per-month efficiencies she had been shown, the new apartment was heaven.

For the last six years, Johnson has had a classic Washington job working for a trade association. Both an accountant and a lawyer, she was in charge of tax policy for the American Institute of Certified Public Accountants. Now she's taking her expertise to New York to become the director of tax practice for one of the nation's larger accounting firms. To a CPA, her three- day trip to New York falls under the category of executive relocation expenses. Globetrotter

Sitting next to Johnson, Dr. Claude J. M. Lenfant whiled away the hours by reading the transcript of his own testimony in a recent lawsuit. Lenfant, who speaks with the accents of his native France, is not a lawyer. Instead, he is the director of international programs for the National Institutes of Health. The one-day trip to New York was part of last-minute preparations for a lengthy visit to Taiwan and mainland China.

Lenfant spent the day in New York discussing his trip to Taiwan with representatives of the American Bureau for Medical Advances in China, one of those holdover groups which dates from America's love affair with Chiang Kai-shek. Since we no longer recognize the government of Taiwan, Lenfant will pay his own way to attend a scientific conference there. There will be nothing unofficial, however, about the jaunt to mainland China where Lenfant will be an official representative of the NIH, just another in the long gray line of government bureaucrats who annually pay courtesy calls on our newest international friend.

As he settled into a second-row seat, Lenfant discovered that he was sitting across the aisle from a familar Capitol Hill figure. Ex-Congressman

For more than 20 years in the House of Representatives, Paul G. Rogers was the man to see about health legislation. After retiring in 1979, Rogers followed the standard route by taking his reputation and his expertise to a blue-chip Washington law firm, in this case Hogan & Hartson.

Although he was traveling alone, Rogers found that there was no need to be lonely aboard the Shuttle. Before taking his right aisle seat in the second row, the former congressman stopped for a moment to chat with his old friends, the Tobins. Seated by chance across from Lenfant, who described him as "looking like a very prosperous lawyer," Rogers also discovered, as we shall see, that he had another buddy in the third row.

Up in New York for the day, Rogers had a brief meeting with a client. But the major reason for the trip was a small working luncheon at the home of noted philanthropist Mary Lasker.

Now 80, Lasker has been in the forefront of the fight against cancer since the 1940s. Recently she began holding exploratory luncheons about launching a new health crusade. According to Rogers, Lasker's latest cause is "advancing a program for research on the problems of aging." Rogers was there, in part, because he had introduced the original legislation that established the National Institute of Aging. Today lunchtime conversation focused on Alzheimer's disease, a serious form of premature senility. Daily Commuter

The right window seat in the third row belonged to David A. Morse, 74, an international lawyer with homes in Georgetown and Manhattan. This helps explain why Morse does this trip four times a week. "Psychologically, I don't find taking the Shuttle any different than commuting to Washington from a house in Middleburg," he said.

Morse, who is a partner in Surrey & Morse (offices in Washington, New York, Paris, London and Jidda), spent the day in Manhattan consulting with two typical clients--the governments of Zaire and Senegal.

The meetings with the financial advisers of Zaire, one of the world's leading debtor nations, concerned the rescheduling of the payments on a series of international loans. He then went to his firm's New York office where he had a lengthy discussion with a Sengalese government official over the possibility of establishing a free-trade zone in that country.

Now Morse was concerned about the flight's one-hour delay because he had a 6:30 meeting scheduled with five politicians--he preferred not to say just who--at the Quality Inn on Capitol Hill.

Before entering private practice, Morse spent 21 years as the executive director of the International Labor Organization in Geneva. In the terminal before the flight, Morse encountered an old friend from the diplomatic circuit and the two of them had decided to sit together. Diplomat

Called "Alex," by friends like the Tobins and Paul Rogers, Alejandro Orfila, who had the left-hand aisle seat in the third row, is the secretary general of the Organization of American States.

During the long wait on the ground, Orfila repeatedly invited Rogers to share his waiting limousine at National Airport, avidly read a local crime story in the New York Post headlined "Tortured to Death" and had a chat with Morse about dictators they had known.

This last conversation began innocently enough when Morse asked Orfila --Argentine dictator Juan Per,on's last ambassador to Washington--whether he had seen Evita. Orfila said that he had been so bothered by the historical inaccuracies about the Per,ons that he didn't enjoy the musical. Morse recalled how impressed he had been on the one occasion that he had met Per,on. Orfila responded with a few Per,on anecdotes. Inspired by these nostalgic tidbits, Morse asked, "You know who was really a fascinating man? Salazar of Portugal."

Like Rogers, Orfila had gone to New York for lunch. His meal was a gala affair for Emilio "Pete" Collado, formerly the executive vice president of Exxon, who was retiring as chairman of the Center for Inter-American Relations. The host, David Rockefeller, had assembled virtually every American corporate executive doing business in Latin America.

As Orfila put it, "When you get an invitation from David Rockefeller for a lunch for Pete Collado, you take the Eastern Shuttle." Lobbyist

As she sat across the third-row aisle from Orfila, Janet A. Riether thought, as she often does on the Shuttle, how much easier her life would be if her office were in Washington. But her employer, the Continental Group, a conglomerate that grew out of Continental Can, insists that their government affairs office be part of corporate headquarters in Stamford, Conn. So Riether, 29, has grown accustomed to Shuttling to Washington two or three times a week, developing a love for the Fairfax Hotel in the process.

Before joining Continental in January as a goverment relations representative (corporate lingo for a lobbyist), Riether, a lawyer, had done the standard Washington stint hopping from jobs on Capitol Hill to the Federal Energy Regulatory Commision. Now she was headed back to town for a meeting at the Washington offices of the law firm of Vinson & Elkins.

At 10 Wednesday morning, Riether joined two Continental executives from Florida at a long table in the conference room at Vinson & Elkins. The other seats were filled with more than 25 lawyers and corporate representatives. Everyone was passionately interested in pending legislation to grant companies the right of eminent domain to build coal slurry pipelines. Not surprisingly, Continental has plans for just such a pipeline on the drawing board.

Riether described the 90-minute conference as "a strategy meeting." The group went through the roster of members of the House Public Works Committee, dividing them into friends, foes and those who needed to be instructed in the wonders of coal slurry pipelines. For lobbyists like Riether, the next step would be to orchestrate visits by Continental executives to wavering legislators.

After lunch Riether became an antitrust expert. The Senate Judiciary Committee is considering a bill that would modify the damages that must be paid by corporations found guilty of price-fixing.

That's fine, as far as Continental is concerned, because it was charged recently with rigging prices for corrugated containers. But because Continental has already settled with the government, and one of their competitors hasn't, they are opposed to a provision in the bill that would make these new modified penalties retroactive.

If you find that hard to follow, pity poor Janet Riether. She had to spend Wednesday afternoon explaining Continental's convoluted position on the bill to aides to Sens. Strom Thurmond (R-S.C.) and Joseph Biden (D-Del.). Interior Designer And His Clients

First another bit of Shuttle protocol: the client is never stuck with the middle seat. This explains the seating arrangements in the fourth row on the right, directly behind Morse and Orfila. Washington interior designer Victor Shargai was in the middle, flanked by his clients Melvyn J. Estrin (aisle) and his wife, Suellen (window).

"All the experienced travelers sit in the front of the Shuttle," said Shargai, who shares many of the viewpoints of his friends, the Tobins. "It's quieter up there. And the people in the front of the Shuttle are used to flying first class. They're the people with places to go and things to do."

Shargai was quite vocal on the subject of the Shuttle, an institution he regards as an unpleasant necessity. "It's the very antithesis of style," he said. "Did you notice how filthy the plane was? The overhead baggage compartment hadn't been washed in years." (According to Eastern, the interior of each Shuttle is scrubbed every 60 days).

The Estrins, who are renovating and enlarging their house in Bethesda, flew up to New York with Shargai Sunday night for a two-day buying trip. As their design consultant explained, "I like my clients to be exposed to everything and it's all in New York. Part of the enjoyment of the job is the trip to New York. It's not all work; it's also fine restaurants and hotels."

Shargai's comments were understatements. The threesome did New York in a manner generally reserved for Arab oil sheiks. They stayed at the Helmsley Palace Hotel where doubles start at $135 per night. Sunday night dinner was at the River Caf,e and Monday lunch was at La Grenouille--needless to say, two of New York's most prestigious restaurants.

But these meals were merely designed to whet the party's appetite for Monday night dinner at the Palace, generally considered to be America's most expensive restaurant. Melvyn Estrin conceded that the bill for the three of them came to more than $600, although he also said "The presentation was magnificent" and "You don't walk away from dinner stuffed, even though there are about eight courses."

After this expensive, but not filling, dinner, the trio stopped off at the Magic disco where there was a party celebrating the end of the Miss Universe pageant. The three of them just strolled in, despite a long line of nobodies waiting outside, because, as Estrin explained, the bouncer had seen them drive up in a limousine.

Before boarding the Shuttle on Tuesday, the group descended on the Russian Tea Room for a little caviar.

To hear Estrin tell it, he had to endure this culinary orgy in order to please his interior designer. "I went to the Palace for Victor," Estrin said. "He wanted to go." Left to his own devices, Estrin said, he would have settled for "a great corned beef and rye sandwich at the Stage Deli."

Between meals, the group roamed the art galleries, antique shops and designer showrooms of Manhattan. As Estrin explained, "We're not talking about department store furniture." Instead, they picked up a late 18th century English hall table and found an elaborate wood carving of heraldic crests. This last piece, which came from an English country house, will have a place of honor as a wall decoration above the Estrins' bar.

By now you may be wondering, as I did: What does Melvyn Estrin do for a living?

He is chairman of the board of a Chevy Chase holding company called the Human Service Group. It's half real estate investment and half government contracting in the social sciences. For example, Estrin's firm operates the National Training Centers for Drug Abuse and Alcohol Abuse. Handshakers

Just across the fourth-row aisle from Melvyn Estrin, were two representatives of the working men and women of America. Raglan George Jr. and Murray Montagh are both union organizers for the Fur, Leather & Machine Workers Union in New York.

They were running late because they had spent most of Tuesday afternoon in contract negotiations with the rabbit fur industry. With the domestic rabbit industry decimated by foreign competition, George said that the union "is almost taking a decrease" to keep their employers in business.

George and Montagh dream of congressional legislation limiting foreign fur imports. But George said, "We're fighting a losing battle on this issue, but we try."

Rep. James L. Nelligan (R- Pa.) is one of the few stalwart friends the domestic rabbit industry has on Capitol Hill. "He has been helping us in our struggle to keep fur shops open because of the imports which are killing our industry," George said.

The two union organizers were flying to Washington to show a little appreciation. On Tuesday night Nelligan was holding a fund-raising reception at the Capitol Hill Club. There was only one problem. The 5 o'clock Shuttle, which was delayed on the ground for an hour, didn't arrive at National Airport until 7. And George and Montagh had to return to New York on the 9 p.m. Shuttle for the Wednesday morning rabbit negotiations.

"It was about the shortest their house trip ever," said Montagh. "But we had to be there. We spent as much time as we could with Nelligan. We did as much as we could in an hour." Washington Lawyer

You could stock a good size law firm just from among the passengers on the 5 o'clock Shuttle. Take Hamilton Carothers, for example, a partner with Covington and Burling, who had the right-hand aisle seat in the fifth row.

Carothers said he's been known to take "the Shuttle up to New York because a telephone conversation was taking too long." This time Carothers' one-day trip to New York was preplanned, but tiring. He had a "friendly discussion" with a client and a "not so friendly conversation with some people that a client of mine may have to sue."

In between, there was a two- hour lunch with officials of the National Football League, which Carothers also represents. "We had some talks about the multiple litigations we have going around the country," he said. Things like the Oakland Raiders' stadium case in Los Angeles.

"Shuttle trips are really remarkable," said Carothers. "It's a rare occasion when I can't recognize five or six other lawyers. I can look around and say, 'There's Wilmer, Cutler; there's Williams & Connolly; and there's Arnold & Porter.' " Diamond Buyer

While we have been fixated on the first six rows of the Shuttle, back in the smoking section Toyson J. Burruss, a financial planner from Marlow Heights, has been trying desperately to look inconspicuous. He has good reason to crave anonymity. Secreted on his body are $55,000 worth of investment-grade diamonds.

"New York is my diamond outlet," said Burruss, who makes a buying trip for clients more than once a week. He is bullish on diamonds as an investment hedge against inflation because, "They don't fluctuate as much as gold." Today he bought diamonds from a dealer in Rockefeller Plaza for an unnamed client--a Washington physician.

Burruss, who was carrying two copies of an investment guide called "The Diamond Book," stressed that a placid demeanor is an important asset in his profession. "When you look nervous," he said, "is when someone does something to you." Like trying to steal the diamonds that are secreted on your person. Also on Board

No single article can capture the mystery, the romance and the pageantry of an Eastern Shuttle flight. The subject deserves a broader canvas--a panoramic novel, a televison docudrama. Left on the cutting room floor are other passengers, other stories.

There's Holly Lane, a Parisian dancer, dressed in tight jeans, a mesh top and white boots. She's returning to the Washington area to spend a few days with her parents. ABC newsman Hugh Downs is also on the flight carrying a blue garment bag. Doug Cornell, a Washington public relations man for the Aluminum Association, has been up in New York chatting with the new aluminum reporter for a trade publication, American Metal Market.

We shouldn't forget feminist Lynda Weston, a Washington-based community organizer with the National Organization of Women's Legal Defense Fund. She has been plotting strategy with the home office in New York.

Because this is reality, instead of one of those Dean Martin airport movies, there were a few stock characters missing from the 5 o'clock Shuttle. There was not one internationally known thief, screaming baby, little-old-lady stowaway, priest, hijacker or pregnant stewardess. There wasn't even former Secretary of State Edmund Muskie.

He took the 4 o'clock Shuttle.