Air maneuvers, daily operations, BonBon's, JuJu Fruits, etc ......... You might call that training kiddo.

The amount of drag is creates is insignificant compared to the amount of visibility you get.
And I believe Motherland and Wrongway posted pictures not from airshows, unless airshows are on aircraft carriers these days.
And when you say visibility, what exactly do you mean? That pilots throw their heads out the window to poke around? Yes, but only in certain conditions. Even a present day plane with a slow stall speed is going faster than most travel in their car. A fly in the eye would be a terrible thing.

Environment has alot to do with such things.
Although I will say that present day commercial, single/twin engine aircraft are quite better for visibility than fighter planes of old.