I did unmanned ISR for 5 years and currently do other stuff...and things.
No, the defense industry as a whole is not recession proof. I was laid off during the sequester and saw that happen to lots of other guys.
The kingair contracts don’t change hands much but it does happen. With that type of flying most guys do it 1-3 rotations or they do it the rest of their lives.
If your former mil and have a clearance or you’re a civilian with a clearance it’s pretty easy to find a job right now if you’ve got over 1000 total time.