Just one small point: fuel vapours are indeed a hazard, and have been known about for years. Most military aircraft get refuelled - to some degree - when shutting down for the day. We used to do this with MB-326H Macchi jets at 2FTS, RAAF Base Pearce, in the 70s / 80s. Same with the Seahawk aircraft operated by the RAN (except there you don't want to over-fill the aircraft, making it too heavy for the planned sortie and therefore having to be de-fuelled). You want to avoid vapour as much as you can.
Have a look around and you'll see a lot of aircraft these days have systems that replace the empty space in fuel tanks with nitrogen as the fuel is burnt down.
Cheers!