The United Airlines flight from Washington to London was only minutes underway when coach passenger Barbara Walker Vaughan started celebrating her 50th birthday.

Reaching into a net bag, the Washington real estate consultant pulled out a spread worthy of a cover on Gourmet magazine: smoked salmon, duck rillettes, a few noble cheeses, even caviar, which she had carefully stowed next to a small ice pack and had properly partnered with toast points. Vaughan arranged the luxurious nibbles on disposable dinnerware and passed them around to her seven traveling companions, thoughtfully remembering the flight attendants with a plate of their own.

Somewhere over the Atlantic, the crew returned the favor, presenting Vaughan and her pals with Champagne from the front of the plane. "You had more fun than anyone in the first cabin," a flight attendant toasted the birthday girl, who spent more on her airborne picnic than she had on her ticket.

Raves for the meals at 30,000 feet? Compliments for the cooking are greater than ever for a growing number of frequent fliers who know that the only way to fly is to bring their own food and drink. Faced with flight delays, incredibly shrinking food service and meals that they'd never look at twice on the ground, these passengers are taking matters into their own hands, tempting--and sometimes annoying--fellow travelers with a lofty smorgasbord of fast-food burgers, down-home barbecue, fish cutlets, whole roast chicken, goodies from Parisian markets and sushi from fashionable restaurants.

The high-flying act has been cleared by the Federal Aviation Administration, which treats such items as carry-on articles that must be safe and stowable, and is sometimes encouraged by the airlines.

As long as your shrimp cocktail is secure for takeoff and you're not overdoing the Limburger cheese, few seem to mind.

"People don't get on board expecting a meal like they used to," says Terri Owen, a representative of the Association of Flight Attendants, who has greeted passengers toting picnic baskets and buckets of fried chicken on her flights. "Airlines have been cutting back dramatically."

Food spending per passenger averaged a mere $4.49 in 1998, slightly higher than the previous year but well below the $6.11 that U.S. airlines shelled out in 1992, according to the U.S. Department of Transportation. Low-cost carriers like Southwest Airlines, which spends less than a dollar a passenger for food service, instruct reservations agents to remind passengers of the company's limited menu--a snack pack of Melba toast, a cheese wedge, cereal bar and beef stick might not sate anyone for the 5 1/2 hours it takes to go from Phoenix to Providence. R.I.

Purveyors are more than happy to pick up the slack and fuel the trend. Travelers staying at any of the world's 35 Ritz-Carlton Hotels can order "Flite Bites" before dashing off to the airport; the takeout service, which began at the Tysons Corner property in 1992 with a croissant, an apple and a bottle of Perrier, has expanded to include exotic fruits in Bali, sushi in Osaka and peanut butter and jelly sandwiches for pint-size fliers.

Several years ago, Hilton Hotels near airports in Atlanta, Chicago and Newark began offering "Food on the Fly"--boxed meals including Cobb salad, cheese steak wraps and seafood pasta, all promoted on the room-service menu. "Guests love it," says John Silvia, the Chicago-based food and beverage director, whose hotel kitchen sells up to two dozen carryout meals a day.

In the nation's capital, the Henley Park Hotel sends its visitors to the airport with "The Red Eye," a choice of sandwich, fruit and beverage for $10.

Passengers who fly with their own comestibles say the practice allows them a measure of control in the uncertain world of missed connections and overbooked cabins. Not only do they recognize and presumably enjoy the food they bring aboard, "you can eat when you want," says David Shaw, media critic for the Los Angeles Times and a jet-setter with a taste for the good life. "I don't have to eat dinner at 4:30 p.m," he adds.

Rudy Maxa, radio's "Savvy Traveler" and a longtime advocate of passengers packing their own meals, calls it "my way to treat myself and pretend I'm in the front of the plane," instead of in coach.

To enhance the in-flight dining experience, Shaw travels with a string bag that contains campers' silverware, a corkscrew, moist towelettes, pieces of aluminum foil and plastic wrap along with what reads like a menu from Dean & DeLuca. "What I take depends on where I'm going and when," says Shaw. Morning flights might take off with Scottish smoked salmon and fresh fruit, while lunch or dinner departures are made smoother with the likes of pate, Italian cold cuts, roast chicken and cheese.

Edible Souvenirs

"I'm not much of a cook, but I love to shop for food," Shaw says. Return trips from France and Italy are preceded by hours spent scouring the local markets for sustenance--enough food to cover multiple time zones and meal times for both him and his family. But even on domestic flights from Los Angeles, Shaw might dive into a deli here, a bakery there, before heading to the airport. "I make every effort to make it as much fun as possible."

So does Libby Strauss, a Miami Beach retiree whose airplane meals "depend on what we have in the house." An early practitioner of the do-it-yourself-dinner, she has been catering her own meals for 20 years. Outbound flights have found her snacking on sliced turkey, fish cutlets and roast chicken from her own kitchen; return trips from Manhattan have included noshes picked up from Carnegie Deli and Zabar's. (Sandwiches are easier to eat when they're cut into thirds rather than halves, she advises would-be food packers.) When coming back from a trip to England, she knows to pick up a good cheese or two to enjoy while crossing the ocean.

Strauss's only rule: "Nothing odoriferous." She's stopped flying with garlicky salami, for instance. "It tends to be nerve-racking for those who are hungry."

Some travelers orchestrate their schedules to pick up takeout food at favorite eateries that they might not have had occasion to squeeze in during business trips.

"There's another opportunity to eat, which is on the airplane," suggests Charlton Blackburne, a vice president of marketing and sales for a mail-order pharmacy based in Louisville. "There are certain foods that only taste good in those cities," the avid restaurant-goer explains.

While traveling from California, he never leaves Los Angeles without a corned beef sandwich from the legendary Canter's or Oakland without breakfast from Roscoe's Chicken and Waffles--mementos he admits tend to perfume the whole plane.

Trips to Chicago inevitably conclude with a taste of one of three barbecue joints--Carsons/The Place for Ribs, Lem's and Leon's--situated near the local airports. "It's a ritual," he says: Pick up the food, return the rental car, hang in the terminal and wait for the flight.

Not everyone savors the idea. Blackburne notices that when he tucks into his stash in first-class, some of his seatmates look on with disdain, as if he were "Granny pulling out possum on 'The Beverly Hillbillies.' " But riding in coach, the typical response to his carry-on food is "Did you bring enough for everybody?"

Veteran fliers agree. "The most common reaction is 'Why didn't I think of that?' " says Strauss. "I feel superior," admits Heidi Yorkshire, a Portand-based wine authority whose carry-on food stash always includes some chocolate. "It cheers you up if your flight is delayed."

Care for Some Ribs?

Miss Manners would applaud the civility of some fliers, who include extra provisions for sharing with seatmates and crew members.

One such passenger is Daisuke Utagawa, owner of the acclaimed Sushi-Ko restaurant in Washington, who has turned down offers from airlines to cater select items from his menu but who travels with enough sushi to whet the appetites of receptive flight attendants.

Another crowd-pleaser is Shaw, whose carry-on delectables help him bond with the crew--and make it easier to get a real wine glass, instead of plastic, from the first-class section of the plane. A while back, the coach-class ticket holder shared a flight with Los Angeles restaurateur and first-class passenger Michael McCarty. Shaw strolled to the front of the plane with treats from his latest shopping spree. "Look, you've fed me well for years," the gourmand proposed to the delighted McCarty, owner of Michael's restaurant. "Let me feed you."

(Flight attendants, many of whom fly with their own snacks, occasionally come to the rescue, too. Terri Owen, who flies for United Airlines, recalls running off a plane during a layover to fetch a meal for a famished passenger who didn't realize his flight was foodless.)

Inevitably, hidden motives spark some of the generosity. Maxa, the radio host, occasionally uses food as a bribe to upgrade from the main cabin. His latest ploy: chocolate cake, picked up at a shop in Paris and paraded before admiring ticket agents at the airport. (They loved the cake but kept Maxa sitting with the masses.)

Hoping to appease a projected 665 million passengers next year, U.S. airlines tread lightly into the subject of self-catered food.

"People need to be mindful," says Al Becker, spokesman for American Airlines. "They're in a relatively confined space and in close proximity." Peeling an orange can send the fruit's fragrance wafting throughout the cabin, say frequent fliers, just as unwrapping a Big Mac allows the tell-tale aroma of fast food to infiltrate air that already is less than fresh.

Some passengers discreetly carry on their own wine for in-flight sipping--a practice that's not encouraged by the airlines but is sometimes overlooked by crew members, who are the only ones who are supposed to serve alcoholic beverages. Bottom line from the FAA: "You can bring alcohol on board, but you cannot consume it," says spokesman Paul Takemoto.

Etiquette and common sense dictate that messy dishes, highly aromatic foods and items that might require special utensils--good luck finding a sharp knife in the air--are best left on the ground. "You need to be self-sufficient," says Vaughan, the high-flying celebrant. "Don't expect the airline to provide anything." Her carry-on includes salt and pepper and small plastic trash bags for easy clean-up.

Remember, too, that you're likely to find yourself elbow to elbow with complete strangers. "What happens when the guy in front leans back in his seat?" wonders Vivian Deuschl, vice president of Ritz-Carlton Hotels and a frequent flier who routinely boards with an emergency stash of energy bars, cheese and crackers and mints.

Appetizing as it is for some passengers, others wouldn't dream of carrying their own food on a plane. "The fact there's going to be a meal never ceases to amaze me," says David M. Petrou, a Washington-based public relations executive who has logged 26 trips on the Concorde. "When I get on a plane, I want it to get me from point A to point B as quickly and safely as possible. I don't look to my airline to be a flying restaurant."

Unlike the Northwest Airlines pilot, a 22-year veteran, who left 150 Detroit-bound passengers stranded at the airport in Las Vegas Nov. 23 when he got off the plane to protest the cold meal he was offered. Passing a lineup of food vendors in the terminal, Capt. Floyd Dean hopped in a taxi and rode off-site, returning more than an hour later with a dinner more to his liking--and less to the satisfaction of Northwest, which fired him Dec. 3.