The U.S. company Delta Air Lines announced today that it will sell broadband wireless Internet access on its entire domestic mainline fleet. The service is expected to be up and running on all domestic flights by the middle of 2009. Wi-Fi will be offered to passengers flying throughout the continental United States.

Aircell, an airborne communications provider, will install the network on more than 330 aircraft that makeup Delta’s U.S. fleet of passenger airliners. The system will allow Wi-Fi enabled devices to access the Internet while in flight. It will cost passengers $9.95 for a flight that is three hours or less, while longer flight time will cost $12.95.

Delta is also considering offering Wi-Fi service for its international fleet and for aircraft used by its regional partners, but has no timetable for installing the service on those flights.