Tom Harvey discovered by accident that the round-trip ticket to New York he had purchased on Orbitz, the online travel site, was really a one-way ticket. He called Orbitz co-owner American Airlines to confirm his vegetarian meal for the April flight, when the agent asked if he realized that he was not returning to San Jose.

Puzzled, Harvey says he called Orbitz customer service, which told him that while Orbitz could issue him a new ticket, he would have to pay double the fare because American had raised prices in the two days since his purchase.

Resource Library:

So Harvey went back to American, pleading membership in AAdvantage, American's rewards program for frequent fliers. It took some convincing, Harvey says, but the agent gave him the benefit of the doubt. He overrode American's new fare and gave Harvey, a marketing director for a California public relations firm, his round-trip ticket at the original price.

American spokeswoman Erika von Hacht won't comment, other than to say that the airline is pleased with its relationship with Orbitz. For its part, Orbitz finds no mention of Harvey's name in its customer service logs and no record of the disputed flight. Employees did pull up a December flight from San Jose to Washington when supplied with Harvey's e-mail address, which is the way Orbitz identifies customers. When Harvey uses that same e-mail address to log into Orbitz's Web site himself, he finds a flight that he took in December—to Baltimore, not Washington.

Such confusion—which also includes errant ticket-price and itinerary information—isn't unusual, according to those who've tried travel sites. And neither is the result: Harvey has stopped using Orbitz and its competitors for business travel. He thinks the risk of a mistake is too high.

Orbitz is a company whose customers have a lot of alternatives—and little tolerance for imperfect service. Neither Orbitz nor its two main competitors (Expedia and Travelocity) have been able to differentiate themselves among consumers—six out of 10 Americans who have used online travel sites have no brand preference, according to Forrester Research.

But the more insidious problem—when you talk to someone like Harvey—may be the number of consumers who've had such bad experiences with online travel services that they've stopped buying through them altogether, and now use them only for research purposes. Since Orbitz's business model is to take a cut of each transaction, such a trend could potentially prove fatal.

Orbitz's future is already in question. A planned sale of stock earlier this year was delayed, and it isn't clear whether Orbitz's cash-hungry owners—American, United Air Lines, Delta Airlines, Continental Airlines and Northwest Airlines—will want to continue funding the fledgling service if the public markets remain depressed. (Travelocity and Expedia are already public.)