Boeing, which launched its Connexion in-flight service in the summer of 2004 and folded it two years later, blew through at least $1 billion looking for enough business travelers who'd pay for the convenience. So far, at least, it doesn't look like Aircell or Row 44 have learned that the gap between what business travelers want and what they'll pay for is a costly chasm indeed.

Of course, in-flight WiFi could possibly prosper without users (or airlines) directly paying the freight. Other third parties could imitate the Google deal with Virgin America. Last week, in fact, Lexus sponsored free WiFi on American Airlines to promote its 2010 cars. Row 44 is partnering with JiWire to develop an advertising-driven portal for free in-flight WiFi. And Boingo is anxious to bring in-flight Internet into its program, which offers travelers access to hundreds of thousands of hotspots nationwide for a flat, monthly fee.

Still, in-flight WiFi providers should be aware that giving travelers what they say they want is risky business. After all, Aircell is only able to offer its ground-to-air Internet service because the company won a Federal Communications Commission auction for most of the radio spectrum once used by in-flight telephones. In the early 1980s, in-flight phones were the high-tech "killer app" that business travelers felt they couldn't live without. But several telecommunications giants and many U.S. carriers wasted two decades and untold millions developing and deploying the Airfone. Seen one on a domestic flight lately?

The Fine Print…

Another drawback for in-flight WiFi: Knowing when you're on an Internet-equipped flight. Only AirTran, with 136 aircraft, and tiny Virgin America, with 28 planes, offer GoGo fleetwide. "Having this available on every flight without an asterisk is a bit of a competitive advantage," says AirTran senior vice president Kevin Healy. Delta, the nation's largest carrier, offers GoGo on about half of its more than 500 full-size domestic jets. American has about 150 planes wired with GoGo. United Airlines has committed to GoGo for just a few transcontinental aircraft. Continental Airlines so far has rejected pitches from both Aircell and Row 44. US Airways says it won't install WiFi until next year. And JetBlue Airways has made virtually no progress deploying an email messaging service through its at-seat video systems.