Full-size Mac keyboards go to F16. IBM mainframe terminals (the 3270 family) went up to F24, and so did IBM PCs specially equipped for mainframe attachment. (For technical reasons too complicated to go into here, the F keys, also known as PF keys, are much more important in that environment.)
I doubt they’d shoot at their own multimillion dollar plane.
I don’t know, might be that guy Ranger Jeff was talking about on the trigger.
You’re referring to the aircraft that the terrorist is stealing so he (or she) can shoot down civilian airliners until he runs out of ammunition? The aircraft that the terrorist is going to use to lob the CBU and Napalm weapons on its wings in to the grand stands of the stadium where the World series or Super Bowl is being held?
If they’ve got to write off the aircraft anyway, let’s try to minimize casualties.
Not trrrsts, a kid at an airshow.
He’s seen the youtubes, flown the simulator. Sees an opportunity and hops it.
There may not even be live bullets within a half mile of the thing. 
I have no idea what he actual procedures are for something like that, but let us assume that said kid managed to get to the airplane in an unattended moment (no guards looking out), get around the security keeping people away when not during visiting hours (i.e. no crowds standing around), somehow figured out getting into the plane and powering up and getting rolling, and not running into a hangar or refueling truck or off the tarmac onto the grass, and somehow is managing to line up with a runway (which conveniently doesn’t have other airplanes using it). I’m sure there’s some sort of a plan of attack that involves loudspeakers and trucks/jeeps prior to engaging anti-aircraft fire/machine gun bursts to stop said kid from taking off and cratering said airplane into the ground.
Do you need a key to start a B-52? 
Sometimes you’ve gotta keep an eye on your pilots: Craig D. Button - Wikipedia
Wasn’t an Abrams, but wasn’t pretty: Shawn Nelson - Wikipedia
What time period? I was on board 85 to 88. (Electrician’s Mate)
They’re not that important, I’ve been programming on IBM mid and mains for about 20 years and the shift key works well enough for the F13 to F24.
Okay, in re the F-16. I got a back seat ride in a two seater F-16 decades ago. I am a 5’2" woman, so I was pretty much gently assisted into the back seat and strapped in. You know I cannot answer the ‘how do you start an F-16’ question–I do know the base had huffers (see wikipedia), and those may have been used to spin the engine up. It was a looong time ago.
It was really kind of a fun ride. I still have the knee card. It was a 2v4, and since I am so short (and flew aerobatics) the blood didn’t have any where to go so I could tolerate the high g forces without much effect. Those were the days you could still get a 9 g pin. Tall men had more problems (there was a breathing maneuver they had to do to keep from passing out).
Anyway, as to armed aircraft on the line, at that base no. Plus the flight line is restricted, patrolled, and so on. I occasionally had to go out to the flight line to pick up people and I had to check in at ops, get a van and a driver, then sit around for a couple of hours until someone would show up late in a jet. Although it looks like controlled chaos out on the line, people know who’s supposed to be out there in what vehicle and what they’re supposed to be doing.
Thanks for bringing back memories.
I had done four generations of code using the earlier 2260 family before the first 3270s were announced. But my point is simply that the PF, PA, Clear, and Enter keys on the 3270 are live, while all the others are not, whereas all the keys are (at least potentially) live on a PC. PC F keys are hardly used at all nowadays, while, without PF keys on the 3270, applications like ISPF are impossible.