I really like this game. Your description is accurate, the game is indeed a rewarding experience for players who stick around. That said, the game also has some minor issues, not outright problems, that if addressed, would improve the experience significantly.
An easier way to restart the game after you've died would save a lot of time in between sessions. While the mission report is useful, maybe having a counter on the side would remove the need for it to appear on the death screen.
The game, while frustrating at times, has a really steep learning curve. I'm having particular difficulty mastering the Vandal, but pretty much have the Arsus and Keener down pat. This isn't an issue, more of a comment on the difficulty of the game, and how, after a grave mistake, a long death screen is the last thing I want to sit through.
Overall, I really enjoy the game. Are you going to add any new planes? The creativity and backstory behind them really adds flavor and gives the game a unique depth, making it that much more enjoyable to blow up "bad guys."
Also, please, please, make a wallpaper of this game. I really like the artistic direction you guys have taken and would love to have the introduction sequence (when the plane is launched from the ocean and the cityscape is visible in the background) as my screensaver on my laptop.
Overall, great job. Thanks for making this game.