Business travelers have long known there can be an upside to the recession: Luxury hotels at bargain rates and fire sales on business-class tickets. But just mention private jet travel in the same breath as “affordable” and you’ll be treated like you had proposed a toast to Bernie Madoff.

Such thinking, or course, has contributed to the private jet business’ current doldrums. Not only have business-jet sales plummeted and private-jet customers been flogged in public for their perceived tone deafness, but many companies have also scaled back use of their remaining jets.

A recent analysis by UBS Investment Research showed that business-jet operations were down 27 percent in September from their peak in 2007, and the number of business jets up for sale rose by 36 percent from a year ago. On Thursday, evidence of that downturn became clear when NetJets—the plane-leasing division of Berkshire Hathaway—announced it was going to fire nearly 500 pilots.

But where most observers see a negative picture, others see opportunity. Several entrepreneurs have come out with new services that could bring private jet travel within the reach of the merely well-off, not just the fabulously wealthy—as well as for corporations seeking a more economical way to continue some private flying on company business.

One key to this forbidden world is the jet card: a product pioneered by NetJets affiliate Marquis Jet that lets wannabe jet-setters dip their toe in by buying blocks of hours aboard a particular type of plane without the headaches—and prohibitive expense—of purchasing a jet or a fractional ownership.

And with smaller, more efficient jets coming on line, the costs of flying private could come down further.

The latest to promote this concept is JetSuite, a southern California startup that in October rolled out what it claims is the first “day card” plan that could undercut competitors’ hourly rates by a substantial margin.

“No one has ever focused on value in private jet travel,” says Alex Wilcox, CEO of JetSuite. “It’s always been ‘If you have to ask, you can’t afford it.’”

“But that is changing,” he adds. “In the last 18 months, people have focused on cost, and they’re looking for a new approach.”

But catering to the ranks of affluent refugees from commercial flying is a risky business, and the past year has seen more than a few casualties: Florida-based Day Jets, which offered an “on demand” air-taxi-style service using the Eclipse light jet, went under in September 2008.

Former American Airlines chief Robert Crandall failed in his efforts this year to win financing for a similar concept, Pogo Jets. Even Richard Branson’s efforts to get into the business flopped: Virgin Charter, which sought to fill the “empty legs” on charter flights that would have flown empty after dropping off customers, went bust last month.

JetSuite is starting off modestly. It has just two aircraft, the brand-new Phenom, a light jet produced by the Brazilian aircraft manufacturer Embraer, which lists for $3.6 million each—less than half the cost of the main rivals in the light-jet category, such as the Hawker 400 XP. JetSuite expects to have a fleet of seven of the four-passenger planes by the end of this year and aims to add one a month thereafter.

With a range of 1,100 miles, the Embraer can fly nonstop to most destinations in the southwest, Wilcox says, with one-stop service bringing the western half of the U.S., within easy reach of Los Angeles. One advantage of using a new plane is the greater fuel economy—the Phenom consumes a quarter of the fuel other private jets require, Wilcox claims.