I do not believe there is a time frame for aircraft to disappear once they are shot down. If there was you would need to extend this greatly and that would also have an impact on frame rates, resources etc. So for low level you would see aircraft there a lot longer than the program allows by default. Anything that uses extra Graphics Ram etc. I would not think worthwhile although if there was such a kick ass machine capable of running it, then it could only be server based. Using your own pc for this would cause too much lag. Imagine everything slowing down just because the graphics were so busy trying to pixilate the falling aircraft.
So no I don’t think this is practical.