This looks like it could be interesting. Moving away from the FPS of the Rainbow 6, Splinter Cell and Ghost Recon, Hawx puts you in control of a selection of more then 50 aircraft with solo, co-op and multiplayer modes. Setting is generic near future, and you'll be playing a Merc facing off against terrorists.
I imagine it'll play in a similar manner to WarHawk on the PS3.
Incidentally, this is also the 39th Tom Clancy game to be announced in ten years and the forth with a 2008 release date (Endwar, Splinter Cell: Conviction and R6V2 being the other three).
Are there any other flight games on the 360?