Paint has to be thinned to go through the airbrush. Not a lot sometimes but it's still not the same as the neat stuff in the can.
What you should do is look at the nearly full paint cup left after spraying and think - I don't want to waste this stuff, I'll pour it back in the tin. It will be fine. There's plenty of neat stuff in there after all.
No it won't.
What it will be is too thin for brush painting. .
Guess how I know this.