CHICAGO (AP) ― Getting stranded at a U.S. airport once meant enduring hours of boredom in a kind of travel purgatory with nothing to eat but fast food. These days, it can seem more like passing through the gates of Shangri-la to find spas, yoga studios, luxury shopping and restaurant menus crafted by celebrity chefs in terminals with a calming, sleek design.

Stung by airline bankruptcies and mergers, more U.S. airports are hunting for alternative revenue streams by hiring top design firms to transform once chaotic and dreary way stations into places of Zen-like tranquility and luxury where people actually want to get stuck ― and spend money. As the holiday travel season is in full gear, airports are putting what one designer calls “terminal bliss’’ on display in hopes of drawing in higher passenger numbers and revenue.

“It’s classy, it’s very classy. ... It makes you feel good about the layover,’’ said Marty Rapp, 70, who was getting rosy cheeked last week with the help of a large glass of merlot under ice-crystal chandeliers at Chicago-O’Hare’s Ice Bar, whose white and softly reflective decor gives the feeling of being secluded in an igloo ― where everyone is drinking and merry.

Airport redesign has been accelerating in the U.S. over the past 10 years, fueled by a combination of things like an airline industry beset by bankruptcies and consolidation that is less able to shoulder as much of the operating costs for city-owned airports through landing fees and gate rentals. More revenue from better retail and dining helps make up the shortfall.

At the same time, travelers are becoming savvier and want more than just to get from A to B. The airport has become almost a destination in its own right, a place worthy of stopping off for a while for a little shopping or pampering.

“There’s the ability to go swimming at some airports, there’s the ability to actually perfect your golf swing at some airports, there is the ability to ― it’s not just getting a quick massage on your shoulders ― it’s almost really going to a spa in some cases,’’ said Bill Hooper, an architect at global design firm Gensler, which has transformed airport terminals, including San Francisco’s Terminal 2, whose abundant natural light, art installations and cool club feel set a new benchmark for contemporary airport design.

The United States and Canada still lag behind Europe and Asia when it comes to the number of airports that are architectural gems and the array of unique offerings. Stockholm’s Arlanda Airport has a wedding package where couples can tie the knot in the control tower balcony. And Seoul’s Incheon International Airport is building a six-level terminal that will include a soaring glass-paneled ceiling giving passengers the feeling they are passing through a terrarium-like wonderland, complete with babbling brook, tropical plants and butterflies.

But American airports are catching up. Space-age-looking redevelopment at Denver International Airport slated to be finished by 2015 includes a Westin hotel and conference center with a rooftop pool and views of the Rockies. With an outdoor plaza for events and a fast new rail line, the airport hopes to be seen as an extension of downtown, about 37 kilometers away.

Dallas-Fort Worth International Airport opened a nearly 1.6-kilometer-long walking path over mosaic floor art inside Terminal D in April. There are two optional cardio step courses leading up 17-meter high staircases, and the path ends up at a free yoga studio, where barefoot travelers with a view of taxiing aircraft can stretch behind light-diffusing screens.

In a sense, airports have taken some of the members-only airline club lounge experience and opened it up for all.

“They’re actually trying to create the same sort of sanctuary concept for the more casual traveler,’’ Hooper said.

Business travelers in particular are catching on and actually choosing which airport they want to spend their layover in based on the offerings.

“Montreal (airport) has a smoked meat place ... that if I’m booking travel and I need to go back on the East Coast, sometimes I’ll say, `Can you get me to Montreal for an hour layover so I can have a smoked beef sandwich?’ “ said Wil Marchant, 40, who works for a financial services firm in Winnipeg.

The transformation is paying off.

Concessions revenue from food, beverage, retail and services at U.S. airports hit $1.5 billion in 2011, up 12 percent from the year before, according to Airports Council International-North America, which represents the vast majority of governing bodies that own and operate commercial airports.

The new business model has helped airports like San Francisco International, which finished a major refurbishment of Terminal 2 in April 2011 with the firm Gensler. The design is sleek, super modern and playful, with children and adults spinning in comfy swivel chairs around coffee tables placed at every gate. Check-in desks ― imposingly high at some airports ― were lowered to look more like hotel concierge desks.

“What we were aiming for is a four- or five-star hotel experience for passengers in the terminal building,’’ said airport Director John L. Martin.

The average spent per passenger at the terminal is now about $14. That’s 22 percent more than domestic travelers spend at the airport’s other terminals.

At O’Hare, where once there was little more than hot dogs and souvenir shops, domestic terminals are now dotted with restaurants led by celebrity chefs like Rick Bayless, piano bars, and a tranquil aeroponic herb garden― a mini forest of green on a quiet mezzanine level.

“It’s pretty amazing. ... I didn’t expect that to be here,’’ said grad student David Janesko, 30, reading a book in a comfy lounge chair beside the garden on his way to see family in Pittsburgh.

But airport bliss doesn’t come cheap, and its price can be a little jarring for passengers.

Back at the Ice Bar 00 which offers 23 different vodkas and four different kinds of ice (crushed, cubes or sphere) ― blues musician and actor Cedric “Catfish’’ Turner was lamenting that his Jack Daniels on the rocks cost $11. But he needed it, he said, to ease a headache from a long layover.

“I could have stolen a bottle,’’ he said with a laugh, his guitar propped next to his bar stool. “I’m a bluesman. Come on, you don’t treat a bluesman like that.’’