Frontier Airlines invited travelers to take part in its "Super Roll" promotion, while Southwest Airlines encouraged America to fly with its "Yes You Can" deals.

United Airlines aimed directly at the ski crowd, while JetBlue targeted fliers looking for warmer climes.

Airlines have unrolled an unprecedented number of fare sales in recent months - some with cutesy taglines capitalizing on sporting events or the presidential election - as they look to drum up business in a sagging economy. In fact, experts say that flying this winter and spring is cheaper than it's been in a long time.

"You can't walk without stubbing your toe on some kind of sale," said Rick Seaney, chief executive officer of travel site Farecompare.com. "We basically have had continuous airfare sales week after week" for several months.

Airfare sales are quite common in January and February, which are among the slower months of the year.

But experts say there are several differences this time around. The discounts, for instance, are steeper than in previous years. Think round-trip fares from Denver to Los Angeles, San Diego and San Francisco for less than $140, Costa Rica for $241 and Dublin, Ireland, over St. Patrick's Day for $460.

The volume of sales also is higher, with some airlines initiating back-to-back promotions. U.S. airlines advertised 25 sales last month alone, up from 19 in January 2008, Seaney said.

Travelers also can find plenty of good discounts even for popular periods, like weekends and holidays. Ticket prices to popular hot spots over spring break, for instance, are down 15 percent nationally and 11 percent in Denver over the same period last year, according to Farecast, which helps travelers predict whether fares will rise or fall on particular routes. Perhaps more impressively, fares from Denver over the next three months are down 23 percent compared with the same period in 2008, Farecast said.

Additionally, carriers are extending the travel time included in the sales to as far as late May and even early June. Best of all, you often can actually find the advertised sale price fairly easily. And hotel prices at many destinations have plummeted, providing a prime time to take a trip - if you can afford it, of course.

"We're seeing some wild and crazy stuff out there," said Tom Parsons, who runs travel site BestFares.com. "Last year we didn't see anything like this. If you remember, a year ago the airlines were instituting new baggage fees and increasing fares almost weekly. I believe the only time I remember sales like this was after 9/11."

The airline industry is benefiting from a free fall in oil prices over the past few months, though many carriers are recording huge charges related to their efforts to lock in fuel costs when the price was higher.

The problem now, however, is that passengers are finally starting to nix travel plans as the nation's economy goes into a deep freeze. While the industry cut capacity in anticipation of such a trend, many airlines are finding themselves with empty seats now that the busy holiday period is over.

"We're seeing fare sale after fare sale after fare sale" in the industry right now, Sean Menke, Frontier's chief executive officer, said during a meeting last week to discuss the company's latest earnings report.

Frontier has had about a half-dozen sales this year, including its recent 48-hour promotion tied to the Super Bowl. It's running a sale through Wednesday that includes round-trip fares to Albuquerque for as low as $105 and Indianapolis for $136.

Tom Bacon, the company's vice president of planning and revenue management, said the carrier has more or less had a sale every week this year.

"From our standpoint, we have some strong momentum going from November and December, and we want to build on that," Bacon said. "We want to remind travelers that there are good values out there."

walshc@RockyMountainNews.com or 303-954-2744