United Airlines (Nasdaq: UAUA) just started to replace Sirius XM Radio (Nasdaq: SIRI) with Microsoft's (Nasdaq: MSFT) Zune channels. The contract with XM [today Sirius XM Radio] ended on May 30, and United Airlines opted against renewing.

With the new player, it's opting for a subtle marketing move. Twenty-one Zune channels should be available on every IFE [in-flight entertainment]-equipped aircraft. For those interested, the 22nd channel will remain unchanged -- United's unique Channel 9 entitled "From the Flight Deck," where you can listen to live communication between the flight deck and air traffic control.

Interestingly, though, the cooperation between Microsoft and United started via Channel 9, because one of Microsoft's executives was afraid of flying and he was told to listen to Channel 9 if he gets "freaked out." It seems that it worked, given that MSDN introduced its own Channel 9 "Inside Microsoft" feature, and now Zune channels will become available on all United flights.

New channels are electronic dance, opera, piano jazz, and soundtracks. As usual, these are prerecorded albums lasting for two hours, just like alleged "live" Sirius XM Satellite Radio, which had nothing to do with satellites. At least not in United planes.

Even though this offer pales in comparison with advanced systems available on Asian carriers such as Singapore Airlines and Cathay Pacific or Middle Eastern ones such as Emirates or Etihad, it is at least a small step forward in much-criticized air travel in the United States.

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