The idea is the plane was stolen in order to cause a kerfluffle to cause the F-15s to be scrambled, then the pilot jumps out, F-15s take out the target. I didn’t realise Ketron was so far from Whidbey though. I don’t necessarily see how there could be a connection.
Listen carefully to these, then compare to the (wild) theories flying around:
STOLEN DASH-8 MAKES AN UNAUTHORIZED TAKEOFF at SeaTac
https://www.youtube.com/watch?v=4LLmF9tZoEE
*PART 2* STOLEN DASH-8 MAKES AN UNAUTHORIZED TAKEOFF at SeaTac
https://www.youtube.com/watch?v=sZC8de10mq0
Hijacked Horizon Air Q400 at Sea-Tac [with ATC audio]
https://www.youtube.com/watch?v=xD5sFrTGFnw
An example of flight simulators and how he might of taught himself just enough to get it in the air:
Tutorial - Dash8 Q400 - Engine Start
https://www.youtube.com/watch?v=hMU5lHXNXZ8