Pacific Fighters.
 

Pacific Fighters is the newest flight sim from 1C Maddox. The same people who brought you the IL-2 Sturmovik series. Of course this game is set in the Pacific Theater. Now I'm not sure if it's another add-on or a new title all together but it looks like it's going to kick ass.

Edit: You can see the video here. Pacific Fighters Video

All new title, but will integrate with IL2 so you can use all the planes and maps. Have fun landing that 262 or p80 on the deck. Fight the battle of midway with Stukas and 109s. Should be fun.