Wireless Internet service could soon allow airline passengers to send messages, surf the Web, and, yes, check in with the boss at about 9400m above ground.

American Airlines expects to have a test plane operating by December and its whole transcontinental fleet of 767s ready in 2008.

Virgin America also plans to equip every seat-back with high-speed capability by mid-2008, while Alaska Airlines will run a test next spring in the hope of outfitting its whole fleet.

Surveys show that as many as 70 percent of passengers want wireless Internet, also known as Wi-Fi, and that many would change airline loyalty for the service.

And so every other major US carrier is watching these experiments closely.

They're also engaged in serious discussions about if and when to wire their fleets, according to broadband innovators AirCell and Row 44, the two major companies providing the technology for planes.

Aviation experts say the advent of Wi-Fi skies is all but inevitable, offering one of the few bright spots on the horizon in these not-so-friendly times when a third of all flights are now delayed.

"Could you imagine a world five years from now where it wasn't the case that you had access to broadband virtually everywhere, including in the air?" says Kevin Mitchell, chairman of the Business Travel Coalition in Radnor, Pennsylvania.

This isn't the first time airlines have experimented with broadband.

Boeing offered a service called Connexion, which Lufthansa and several Asian airlines, used in 2004.

But in August 2006, Boeing discontinued the service, saying the market they'd anticipated hadn't materialized.

Part of the problem was that the antennas used to pick up satellite signals were heavy and only appropriate for wide-body planes like 747s. The antennas created drag and increased a plane's fuel burn. Also, because so few planes were equipped with it, passengers sometimes were unaware Wi-Fi was available.

"Anybody that used it, loved it. For $30, you got eight hours of productivity on a transatlantic flight," says Robert Mann, president of RW Mann & Co, an aviation consulting business in Port Washington, New York. "Unfortunately, it never broke out of an introductory, beta-test pricing model."

Five years after Boeing started its Connexion experiment, antennas are now lighter and less expensive and can be installed on everything from a Jumbo 747 to a regional jet. Even the type of broadband offered has expanded.

AirCell, which is servicing American and Virgin America, is using a ground-based technology that accesses existing cell towers.

Row 44, which will provide broadband access to Alaska Airlines, is using a satellite-based system like that in Boeing's Connexion.

"We don't have to build any ground infrastructure," a spokesman said.

But AirCell's executives are just as adamant that their system is superior because it uses the vast network of cell towers already in existence.