While other U.S. airlines have struggled over the past decade from the ups and downs of the economy and the price of jet fuel, Allegiant Air has been profitable for 10 straight years.

The tiny airline focuses on a niche ignored by other airlines: It only flies from small cities to sunny vacation spots, including Fort Lauderdale.

Allegiant entices people who otherwise wouldn’t fly with low fares and non-stop flights. Then it aggressively pitches them hotels, rental cars, show tickets and other entertainment, earning millions in commissions.

Passengers face fees for almost every service and amenity imaginable. At Allegiant, fees for checked baggage and changing an itinerary – which are common on many airlines – are just the beginning.

The Las Vegas-based airline charges extra to book flights online, or to use a credit card. Selecting a seat in advance costs $5 to $75 each way, depending on the length of a flight. Even a bottle of water costs $2.

Flying Allegiant isn’t glamorous. While other airlines tout new aircraft with Wi-Fi and TVs in every seat, Allegiant buys old planes to avoid hefty aircraft loans. And to pack in as many passengers as possible, its seats don’t recline. But for small-town Americans with limited flight options, these inconveniences are worth it for a few days of sunshine.

“They could be the worst airline in the world and we’d fly them because we want to go to Vegas,” says Tom Mayo of Cedar Rapids, Iowa, who recently flew there with his family. “It’s our only option.”

Allegiant offers non-stop service from places like Owensboro, Ky., Casper, Wyo. and Appleton, Wis., to popular destinations in Nevada, Florida, Hawaii and Arizona. (The airline flies between Fort Lauderdale and eight cities: Asheville, N.C.; Grand Rapids, Mich.; Greensboro, N.C.; Greenville, S.C.; Huntington, W. Va.; Knoxville, Tenn.; Lexington, Ky.; and Plattsburgh, N.Y.) These may not be the most coveted routes in the airline business, but that is precisely why Allegiant likes them.

Only 17 of Allegiant’s 203 routes are flown non-stop by another airline.

“Typically, the best way to make money is not to compete with somebody,” says Andrew C. Levy, president of Allegiant Travel Co., who sits in a cubicle next to the rest of his staff.

Rather than battle major carriers for customers on routes between major cities, Allegiant uses its marketing muscles to convince people in small towns to fly away for a vacation.

“Allegiant tends to bring people into the airport who wouldn’t normally fly,” says Tim Bradshaw, director of the Eastern Iowa Airport in Cedar Rapids. “It brings people off the couch.”

Last year, 7 million passengers took a flight on Allegiant. That is a sliver of the 642 million people who took a domestic flight last year. But Allegiant earned a whopping $11.22 each way from those passengers. On average, the airline industry earned 37 cents each way, per passenger, according to Airlines for America, the industry’s lobbying group. Southwest Airlines, one of the industry’s most profitable carriers, made $3.85 per passenger last year.

Allegiant is ruthless about keeping its costs down. Its employees are some of the lowest paid in the industry, in some cases making $20 an hour less than colleagues at other airlines. It pays cash for airplanes nearly twice as old as everyone else. It only sells directly to vacationers, refusing to pay Expedia, Orbitz or other sites to list its flights.