The standard Boeing Co. tour includes the world's largest building, where the world's largest jetliner is built by the world's most successful airplane manufacturing and leading U.S. exporter.

Boeing, an economic basket case a decade ago, now so completely dominates the selling of new airliners that one must question whether McDonnell Douglas or Lockheed can seriously compete much longer in the commercial side of the aerospace business.

Nobody at Boeing bothers to pretend it is any other way. Is there any competition? John M. Swihart, Boeing vice president for domestic sales, was asked.

"There is significant competition," he said, "from the Airbus." The Airbus is built by a consortium of Europeans, primarily the French and the [West] Germans.

"Their governments are behind them and they are determined to keep a significant number of employes" in aerospace, Swihart said.

New airplanes are suddenly a much desired commodity. The big four-engine transports that inaugurated jet travel for commercial passengers -- the Boeing 707 and McDonnell Douglas DC-8 -- are now well into their 20s and are being retired as quickly as possible.

They are horribly noisy and require enormously long runways, but the primary reason they are being retired is that they use a lot of jet fuel. Jet fuel cost about 12 cents a gallon when they were built; now it costs about 90 cents a gallon.

The airlines, despite their own economic difficulties, are forced to move forward with aggressive plans to buy new fuel-efficient fleets, because fuel now accounts for more than 30 percent of airline operating costs; in the good old days it was about 12 percent.

In the next 10 years, the major airplane manufacturers generally agree, there should be a worldwide commercial jetliner market for about 5,000 airplanes that will sell for more than $100 billion in 1979 dollar values.

Given that potential, Douglas and Lockheed -- two of the most revered names in aviation -- could be expected to be on the street with wonderful new airplanes.

Instead, Lockheed is pushing "stretch" derivatives of its one existing commercial jetliner, but is really offering nothing new.

In the last year, Douglas has shelved plans to stretch its DC10 wide body but seems unable to make the decision to spend the $1 billion to $2 billion it would take to get an all-new transport off the ground in direct competition with one of Boeing's new planes. Douglas insists its recently certified DC9-Super 80 is more than just another stretch of its mainstay DC9, but not all airlines agree.

Boeing, meanwhile, has under construction in factories near Seattle the first production models of two brand new airplanes, the 757 and the 767, and is talking about stretching the 767 before the first standard model is delivered. Boeing is also considering stretch derivatives of its existing smallest and largest models, the 737 and the 747 respectively.

Given that situation, it has become a central concern of major U.S. trunk airlines as to whether they are going to be left with Boeing as the only U.S. manufacturer. "Obviously we're in favor of competition among our suppliers. We get a much better quality product," said Robin Wilson, senior vice president for operations of Trans World Airlines.

Wilson said that in his view it was unlikely that either Douglas or Lockheed "could ever become a full-line manufacturer.

"We'd dearly like to see Lockheed and Douglas competing with Boeing in separate segments of the markets," Wilson said. "If each could develop a niche, it would be good for Boeing as well as the industry."

Boeing, of course, speaks no ill of weak relatives. "Every one of the major trunks [carriers] feels very strongly that they need tough competitors in the market," Swihart said. "I believe that too. We turn out better products when we have tough competitors."

Then comes the Boeing confidence, which almost borders on arrogance. "I think we can win because we've poured more into research and development," Swihart said. "On a world-wide basis, we have tended to hold 55 percent of the market. We've lost some competitions in the Middle East and lost some in the Far East. But I think on balance we'll probably hold [at about 55 percent]."

Translation: If Boeing is going to retain its market share, and Airbus is the competition, then the losers are Douglas and Lockheed.

Both Lockheed and Douglas have had cash-flow problems for years as they engaged in head-to-head competition selling two very similar airplanes. Neither could win.

The planes, both three-engined wide bodies, are the Lockheed L1011 and the Douglas DC10. Both production programs will apparently edge into the black sometime in their second decades. But the economic drag they have placed on their companies is enormous.

"The country probably hasn't benefited from that competition," TWA's Wilson observed.

While Lockheed and Douglas have been knocking each other around in the wide-body trijet market, Boeing has been making one of the great economic recoveries. The bottom came in the early 1970s. The 747 had cost an enormous amount of money to develop and was not selling quickly enough; the Congress had decided that there would be no U.S. supersonic transport, and Boeing lost that prize (which may, in retrospect, have been a break).

"We had way too many people around here," said Pete Bush, director or corporate public relations. "We had added people to solve problems but they were diluting management and the skilled work force. We wound up being overpopulated."

Boeing went from 101,000 employes in the Seattle area to 35,000 in the early 1970s, a drop that was devastating to Seattle's economy. Now Boeing is back to about 85,000.

"The biggest thing now," said Bush, "is that we're immensely more productive than we were. Fewer people do more . . . and we invested a lot of dough in tools."

The higher productivity of Boeing's tooling is obvious even to a layman taking consecutive tours of the Douglas, Lockheed and Boeing assembly lines. One giant new gadget on the 767 line automatically locates, drills and countersinks the holes, then places and finishes 85 to 90 percent of the hundreds of rivets on a wing. Older tooling required hand placement of almost one-third of the rivets.

But Beoing's drastic cutbacks and productivity gains were aided by the remarkable sales performance of the ubiquitous 727: "One of the few money trees that ever was produced in commercial aviation," in the words of Edgar M. Cortright, president of Lockheed-California Co., which builds the L1011.

"The 727 was a wonder airplane from that point of view. It fit the market perfectly and had no real competitor, the kind of position everyone would like to be in."

Furthermore, foreign sales of the 727 filled positions in the assembly line. That fact in Boeing's history must be one of the reasons its officials talk with such respect of Airbus, because Airbus is taking the European market away, and the European market helped save Boeing.

"We're not going to sell 767s in [West] Germany and France," said Dean Thornton, vice president-general manager of Boeing's 767 division.

John Brizendine, president of the Douglas Aircraft division of McDonnell Douglas, complained in an interview in Long Beach, Calif., that "when we face Airbus Industries, fairly often French President Valery Giscard d'Estaing shows up, because they do forcefully support" their industry.

Another factor in Boeing's resurgence has to be the quality of its top engineering and management people, a tribute to the personnel selection skill of Thornton "T" Wilson, chairman of the board.

"At Boeing you get layer after layer after layer of class acts," said a federal official with wide experience in dealing with the three major manufacturers.

With the combination of sharp management and an immensely popular airplane generating cash, the situation now is that Boeing has something to offer just about every big airline. The lineup:

The 737 has about 100 seats and a range of 1,900 miles; a stretched version not yet committed to production would offer about 130 seats. The twin-engine 737 has head-to-head competition from Douglas' DC9.

The 727 can carry 143 people and has the same range as the 737. More than 1,500 of the T-tailed trijets have been delivered and 83 orders have been placed this year alone.

Nonetheless, the economics of fuel efficiency and noise abatement requirements are going to catch up with the 727 before too many more years, in the opinion of industry observers, and its remarkable run will come to a close.Douglas' new DC9-80 is the first real competition is this size.

The 757, one of the two new Boeing planes, will be a narrow-body twin-engine with the same width and slightly more range than the current 727. It will carry about 175 passengers. Boeing regards the 757 as the logical successor to the 727, and has taken 52 orders, with the first delivery scheduled in January 1983. There is no effective competition in this size at this moment.

The 767, the other new plane, will be a twin-engine wide body with about 210 seats and a range of 2,900 miles. There are 161 orders from 13 different airlines for this plane and the first delivery is scheduled in August 1982. The chief competitor here is Airbus Industrie with its A310, although versions of both the L1011 and the DC10 can claim to be in this class.

The 747. There are seven versions of the giant four-engine 747, from the 331-seat SP to the standard large model with 452 seats. The range of the 747 varies according to model from 4,600 miles to 6,400. More than 500 have been sold and Boeing is studying a stretch model with as many as 650 seats. The DC10 and to a lesser extent the L1011 have been competitive at times with the smaller 747s. A new stretched version of the L1011 should help Lockheed's position here.

The 707, Boeing's first commercial jetliner, is still being manufactured, but only as a platform for the Air Force's Airborne Warning and Control System (AWACS).

This family of airplanes gives Boeing an enormous competitive advantage. "I've shifted out of 767s into 737s in talking to airlines," said G. Myron Anton, marketing director for the 767. "We all work for Boeing.Our objective is to get happy customers out there and make sure they have the right airplane."

Douglas' Brizendine is an admirer. "Boeing has proven the value of the family of airplanes very well, from the smallest to the largest," he said. The idea was "either well conceived or damn lucky, one of the two. I'll give them credit that it was well conceived."

Boeing is pressing for yet another market advantage.The 757 and 767, if Boeing's plans win certification from the Federal Aviation Administration, will have essentially identical cockpits. The crews will theoretically be able to fly either plane with training on just one. The cost benefit to airlines is obvious.

boeing is also offering cockpits in both two-person and three-person configurations, and participated vigorously in arguing the safty of two-person crews last summer when the Air Line Pilots Association attempted to block FAA certification of the DC9-Super 80 because of its two-person crew. Boeing clearly wanted to block any precedent that would prevent certification of an airliner with only two crew members.

So while Boeing grows and grows, Lockheed and Douglas count their pennies in hopes of finding enough cash to stay in the marketplace. The L1011, the DC9 and the DC10 have some years and many sales left in them, but the future is uncertain.

Lockheed's Cortright insisted in an interview in Burbank that Lockheed is not going to abandon the commercial field. "Our projections show a very large market throughout the coming decade and we think . . . well, I could say this: Boeing doesn't make everything that the market needs," said Cortright. "The thing they notably don't make, and neither does Airbus, is a tri-jet. . . .

"If I can make a self-serving statement, matching Boeing technically has not been a problem. We think we've led all of the U.S. producers in commercial aircraft in technology. We can still do that. But in generating cash to keep our plant modern, that's a challenge."

Douglas' Brizendine obviously wants to proceed with a new Douglas plane, currently called the DCXX, that would complete head-on with the 757. To do that, Brizendine needs the go-ahead from the parent McDonnell Douglas Corp. board and the longer that decision is unmade, the more likely it is that it will never be made.

James T. Burton, director of commercial marketing for Douglas, said Boeing is "most vulnerable in the 757. It's a damn good airplane, but it can be done better. They had their first string on the 767. I don't think their second string is as good as our first string. We see that as an opportunity. . . . We have airlines that agree with us."

But isn't the basic problem overcapacity in the industry?

"There is a lot of evidence that says we have overcapacity," said Burton. "Somebody has to step out. Lockheed has to face that."