Ichromo recently announced their upcoming propeller-powered flight simulator, Aera. According to their web site, the gameplay is "a mix of side-scroller and flight simulator" featuring aerobatic, dog fight, race, and free flight game modes.
The developer has been fairly active posting in the thread announcing Aera's upcoming release, and has shed some light on a few things. First off, the game is controlled using the accelerometer, tilting right and left controls the pitch of your airplane and shaking the iPhone sends your plane in to a barrel roll.
Aera is set in a 3D world, but controls closer to a sidescroller as horizontal movement is controlled automatically. Also, aside from the single player campaign modes, two player WiFi multiplayer will be included in the initial release, with Bluetooth peer to peer connectivity being added later with an update.
That's all we know right now, but I encourage everyone, even if you're not normally interested in flight games to watch the trailer. It's one of the more impressive ones I've seen, and needless to say, we're going to be keeping a close eye on Aera's development.