I got 10 planes! (proof: )
Edit: 12 now
Initially I was confused, especially since the UI looked like this:
It was only after I zoomed out my browser tab that it looked normal. For a game with minimal instructions, the gameplay is surprisingly intuitive after one game. A very cool puzzle, but I do wish there was a bit more to it. I know that you probably feel the same way, so if you end up continuing to work on this, I'm excited to see where it goes. Good work!