Live TV, the JetBlue unit that operates the system, is rolling it out in partnership with Yahoo (YHOO) and BlackBerry maker Research In Motion (RIMM). Users can send and receive e-mail from any type of account on two models of BlackBerry, 8820 and 8320. Laptop users are limited to using only Yahoo e-mail and Yahoo's instant messaging application. The companies haven't signed exclusive deals, and JetBlue may opt to include other popular web-based e-mail accounts in the future, such as Hotmail or Gmail.

During a news media test flight on Wednesday, the service failed to start for about 20 minutes once the aircraft cleared the required altitude for electronic devices. Users can also expect several minutes of disconnection when the aircraft flies over spots where transmission is being relayed from one ground tower to the next.

One reporter had difficulty composing and sending e-mail from his Yahoo account, even though he was able to reply to incoming e-mails. E-mails he sent from a BlackBerry provided by JetBlue never reached his intended recipients even though the device confirmed that they were sent. Another reporter had difficulty receiving and replying to e-mails in her Yahoo account.

Nate Quigley, CEO of LiveTV, acknowledged that the system is a work in progress. He said software upgrades will be made to work out the kinks. JetBlue chairman and founder David Neeleman, a self-described "Crackberry addict," was aboard the test flight and declared the service "pretty cool."

JetBlue has been hinting about offering the service since June 2006, when LiveTV bought a small portion of the wireless spectrum abandoned by Verizon Airfone, which used it for the now-defunct seatback phones.

Because of its spectrum's bandwidth limits, the carrier has said it'll limit its offering to the Internet services that are most desired by business travelers: e-mail and instant messaging. Business traveler Scott McKain of Indianapolis says the ability to access e-mail would make a big difference in his choice of airlines, "even more than frequent-flier miles or other perks."

In-flight Internet access is off to a halting start worldwide. Last year, aerospace giant Boeing (BA) cited slow sales to airlines in closing its Connexion by Boeing division. It had provided broadband service to a handful of foreign carriers. Now, a half-dozen smaller technology companies are jockeying to offer it to airlines.

American Airlines (AMR) and Virgin America are working with Colorado-based AirCell to offer the service in 2008. Alaska Airlines (ALK) has signed with a California technology firm, Row 44, to begin the service starting in 2008. Southwest (LUV) has also said previously it hopes to launch the service next year.

Unlike its on-board TV service, JetBlue's Wi-Fi connection doesn't rely on satellites. Instead, it uses an antenna on the aircraft to transmit signals to about 100 ground cell tower stations. The aircraft antenna connects to the server on board. Three Wi-Fi connecting points on the aircraft sends and receives data to and from the server. Without satellites, the service is limited to mostly over land. Due to federal regulations, it can only be turned on once the aircraft clears 10,000 feet.