If you pay up for the game now you can download and play Blazing Angels: Squadrons of WWII for free. The 2006 released game (developed by the same team that is making H.A.W.X.) normally sells on Steam for $9.99. If you haven't played the game before it should keep you occupied while you wait for H.A.W.X.'s release in mid-March.
Gallery: Tom Clancy's HAWX