A-1 … a whole new concept! Yes, the P-51 was designed as a long-range escort with the capability of acting as a fighter-bomber. In the latter capacity, it attacked German planes on the ground or during take-off or landing, as well as other targets of opportunity. This fighter-bomber capability was very important for destroying German jet planes (and their pilots) (think of the ME-262) that we could not fight well in the sky. The concept of the A-1 (embodied in the A-10 of today) is a plane that can survive while operating in a ground attack role when the enemy is throwing up a lot of small arms fire. Because the vital organs of the plane are protected by positioning and armor plating, the A series plane will often come back from a mission full of holes that would have crippled a plane not designed to operate in such an environment. I suppose there is a trade-off of speed, range and maneuver to gain this level of protection. I did not know about the A-1, so thanks for the tip.
Well, the progenitor of the idea is the Russian IL-2 Sturmovik. We don’t have any of those, though.
https://en.wikipedia.org/wiki/Ilyushin_Il-2
Actually, the A-1 had incredible range - 1300+ miles on internal fuel alone. Wasn’t terribly maneuverable, but it was competent and several of them actually were able to shoot down fighter jets in combat. Their cruise speed was about 200mph, which was just fine for a ground attack aircraft; it let the pilots loiter for a very long time - Skyraiders in Vietnam could hang out over targets for literally *hours* providing ground support. A fully fueled Skyraider had a flight time of up to ten hours.