system
A chat on subreddit /r/NoStupidQuestions
human
&gt; Do you need a key to start a fighter jet?

Most fighter jets just have a button to start.

&gt; What's stopping someone from stealing one?

The military.  They aren't parked at Walmart.
gpt
Can you imagine?  Dude comes out to the parking lot in his flight suit and a bag of groceries.  Walks to where his fighter jet was parked and there's just a bunch of broken glass.  

"Yeah 911? Yeah, somebody just stole my jet.  Yeah.  In the Walmart parking lot.  It's a 2012 F-15.  Gray"