‘‘I don’t think of them as an airline. I think of them as a travel company,’’ says Helane Becker, an airline analyst at Cowen Securities.

Once onboard, Allegiant passengers are again bombarded with sales pitches. On a recent flight from Cedar Rapids to Las Vegas, flight attendants came over the loudspeaker and hawked show tickets and airport shuttles. The in-flight magazine is filled with ads for shows and attractions instead of stories. One ad offers $30 off a Las Vegas helicopter tour if purchased from flight attendants, who are paid extra for each item sold.

‘‘They do a fantastic job packaging,’’ says JetBlue CEO David Barger. ‘‘I think we can learn a lot from what Allegiant does.’’

Ben Baldanza, CEO of Spirit Airlines — the only other U.S. carrier to charge for overhead bin space or for booking over the Internet — also respects Allegiant’s ability to sell extras, such as a round of golf in Myrtle Beach, S.C.

‘‘They developed that expertise earlier than we did,’’ Baldanza says.

Spirit focuses on getting passengers between big cities cheaply; Allegiant taps into people’s desire to escape small-town life for a few days.

Most airlines promote their new first-class seats or individual TV screens. Allegiant — which only offers coach seats — promotes its destinations: Las Vegas gamblers smiling after winning at roulette, a hot-air balloon floating over the Arizona desert or a woman in a bikini sipping a frozen drink on a Hawaiian beach.

Allegiant’s passengers aren’t sold on the airline but on the escape.

An hour and a half before a recent flight from Cedar Rapids to Las Vegas, a spare seat couldn’t be found in the airport bar. It was only 11 a.m., but travelers like Bridget Estrada and her four friends were too excited for their trip to wait.

It was only Estrada’s second trip on a plane and her first in 13 years. She was nervous and gave a quick thought to her husband and three kids at home. But she and her friends quickly got back to drinking hard lemonade, mapping out their weekend away from Iowa.

A few feet away, other passengers shared tips on attractions, buffets and the cheapest blackjack tables.

‘‘You must see the pirate show,’’ one insisted.

Allegiant finds ways to profit on routes other airlines couldn’t make work, often swooping in after they pull out. This month, it started flying between Asheville, N.C., and Tampa, Fla., a route abandoned by AirTran after Southwest Airlines acquired it.

Like other discount carriers, Allegiant prefers small airports that charge airlines lower rents, even if they aren’t the most convenient. In Orlando, that means flying into Sanford, Fla., 30 minutes further from Walt Disney World than Orlando International Airport.

Frugal decisions like that helped Allegiant post a net profit of $78 million last year on revenue of $909 million. Its 8.6 percent profit margin was the highest of any U.S. airline, making it a darling of Wall Street.

The last five years have been good for airline investors. After a major spike in fuel prices in 2008 and a drop in business travelers, airlines tweaked their business models, adding baggage fees and cutting unprofitable flights. They started to make money and their stock prices climbed. While the S&P 500 climbed 26 percent in the past five years, an index of all U.S. airline stocks has tripled. Allegiant’s stock has done even better, increasing more than fivefold to $105.40

Allegiant has 64 planes and flies to 87 cities, but it’s tiny compared with an airline like United, which carried 20 times as many people last year, often on much longer flights.

The airline got its start in 1998 as a charter operation with one airplane. By February the following year, it had started scheduled flights between Fresno, Calif. and Las Vegas.

But its business struggled and less than two years later, it filed for bankruptcy protection. Maurice J. Gallagher, Jr., the airline’s major creditor and a founder of ValuJet Airlines, gained control during the reorganization and became CEO. ValuJet was a low-cost carrier that changed its name to AirTran after a 1996 fatal crash in Florida.

Gallagher moved the airline from Fresno to Las Vegas; secured a lucrative contract with Harrah’s to provide charter services to its casinos in Laughlin, Nev., and Reno, Nev.; and started to transform Allegiant into a low-cost carrier.

‘‘The model evolved out of survival,’’ says Gallagher, who is still CEO.