A new Web-based company promises to revolutionize the way flexible vacationers buy airline tickets - by letting them set the price they're willing to pay.

But Priceline.Com, which launched April 6, faces a bumpy ride in the booming but still unprofitable on-line travel industry.

Consumers who book through Priceline.Com list their destination, travel dates, a round-trip fare they'd accept, and a credit card number that will be charged if their price is met.

Priceline.Com sifts through an inventory of unpublished fares supplied by a dozen major (but unnamed) U.S. and international carriers. That process is completed within an hour for domestic flights and 24 hours for international trips, and Priceline.Com issues a ticket if an airline is willing to release a seat at the requested price.

To weed out business travelers, the company includes stringent restrictions: Customers must be willing to fly on any participating airline and depart between 6 a.m. and 10 p.m. Flights may include one stop or connection. Priceline.Com travelers don't earn frequent flier mileage, and while their first request (for up to eight tickets) is free, subsequent requests for the same itinerary on the same dates cost $25 each.

Travelers who don't have Internet access can place requests through a toll-free number (800-774-2354) for $5.

In theory, that willingness to be flexible should help airlines fill some of the 600,000 seats that go empty every day. And it could translate to significantly lower-than-advertised fares, particularly for seniors and fliers who can't meet Saturday night and advance purchase restrictions.

But ''we're not a discount ticket warehouse, and we're not for everybody,'' says founder Jay Walker, who will add new cars and mortage rates later this year.

Indeed, consumers may not be willing to book a flight without seeing a list of participating airlines, says Richard Eastman, president of the Eastman Group, a travel software and consulting firm.

"Down the road, I think this concept has great validity," he says. "But you've got to re-educate buyers." "Priceline.Com is the latest example of efforts to challenge the airlines' traditional ticket distribution system. Many carriers now offer steeply discounted, last-minute Internet fares, and a handful - most notably Cathay Pacific - have experimented with on-line ticket auctions. But other Web-based companies featuring ticket auctions have failed.

"We're still in uncharted waters," says on-line travel consultant Philip Wolf.

By Laura Bly, USA TODAY

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