Pretty nicely executed experience, felt quite polished. I would have liked to have a way to select or lock on to a plane using my keyboard so that I didn't have to keep switching between mouse and keyboard with my right hand as I played. Also, it wasn't immediately clear that I was sending a message to the attacking planes rather than shooting them down with the code. Maybe having the planes visibly turn around and fly away would be a good indication of this. Finally, I liked the feel of the missile drop sequence but it seemed a little too easy.
Game looks really nice though, I'm a big fan of the art style. Good job!