I really like the controls, how you drag by rotating the planet, the difficulty curve was good untill like 45-55 planes were spawning quicker than I can find. but the different plane types were good.

One thing you should do is when there is an alert slow the game down and make it easier to find planes without paths. like a button on the side that will center you to the plane.

I also got lots of alerts from newly spawned planes that spawned from airports that another plane was just landing at, was a little annoying having it flash up then disappear. and when clicking on a plane i would get disoriented as it would rotate the planet around so my left before may be up now, couldn't find a few airports because of that

At first it was super relaxing(nice graphics, really relaxed music), then became somewhat frantic. I finally got overwhelmed at 50ish. That felt like a good progression.

The presentation is good and easy to read, the rotation is sometimes a little wonky but that's quaternions for you.
The way you interact is clear and most of the time you have no problems to execute what you are trying to do. A few times the auto-rotation made me mess up a bit. Correcting those mistakes was quick to do though.

Well done :)

Fun little game! I included it in my Ludum Dare 38 compilation video series, if you’d like to take a look :)
https://www.youtube.com/watch?v=tDuO7KTgNEs