Current day aircrafts depend on sheer speed, anti-radar technology (i.e. extremely basic stealth technology), jamming, and surprise to survive. The A-10 only has a reinforced hull because of the way it attacks (think of a sideways figure8 where the target is at the center) prevents it from abusing high speed and once it attacks once the surprise is no longer there lol. That thing is surprisingly durable though, i used to be Avionics for the airforce and while i didnt work on the a-10 it was in my job description so i had to learn about it in tech school. The amount of stories/claims of that thing basically losing its wings and still do its **** job is scary.
That being said though, there are numerous examples even today where a plane took a payload and didnt explode or crash afterwords. Sure as hell set off every alarm the plane has and the pilot was probably crapping bricks and rightfully so, but hes still there. Unless the explosion cut off a chunk of the main fuselage, took out the pilot, or killed the engines odds are its still capable of war. Taking out plane engines is the easiest way to get rid of them both in the old days of rotary engines and modern jets. Thats why AA weapons are typically FLAKK weaponry. Throw gunk down that intake, that plane is done and unless that particular plane can glide REALLY **** well (not many can) he is not getting home.
Thats why majority of the crits in xwing are so brutal. If a chunk of your maneuvering thrustors just went offline, yeah you can still do your job but you are going to be severely stressed out trying to do it with a reduced functionality ship. Im actually surprised there are any mild crits, ironically the stress one being the most tame to me.
Not an expert here, but aren't helicopter gunships pretty heavily armored? I know it's not fixed wing, which is what you were talking about, but it's another example of armor on an aircraft.