Superman's "supersonic" flight's legality?

[JulianPerez]

Superman is capable of moving at incredible speed, AND Superman is dedicated to obeying the law, two things that may not be compatible.

Supersonic aircraft, like the Concorde, are limited by where they are able to fly because of the havok, noise and environmental damage of supersonic travel. Intriguingly, the same is also true of Avengers Quinjets; they cannot fly over Manhattan proper, for instance.

Is it possible there are rules for where Superman can fly and not fly, and how fast, legally? Probably not, because of Superman's widespread popularity. But he may follow certain kinds of laws himself for air travel, speeding only in designated air corridors, and so forth.

Though it may be likely Superman tries to avoid going to full speed for fear of the wind and the sonic booms and other effects, and waits till certain alltitudes to really pour on the speed. There is some evidence Superman does just that; he seems to move considerably more slowly in urban areas, fast enough to be seen.

[Continental Op]

For most of his history, Superman seemed to have some kind of conscious control over the negative effects of his super-stunts. Partly it's just that physical laws are different in the DC Universe. The same thing goes for the Flash. They seem to be able to create the negative effects if they WANT to, but it's not usually a problem otherwise. For example, the Flash's invisible "aura" always protected anything he held from burning up due to friction while moving at super-speed. But sometimes he COULD use super-speed friction to destroy something clinging to him.

In the first few years post-CRISIS, DC seemed to be trying to make things more like real-world science... Wally West couldn't go above the speed of sound, and Superman's powers were more psionic than physical, so he was unknowingly using telelkinesis to avoid damage to his environment. The first time Wally tried to move at Barry Allen speed, he almost killed himself and devastated the whole area. That idea vanished eventually and the DCU is back to more "unrealistic" powers.

One time I remember it being a problem was that Barry wasn't paying attention and created a sonic boom while running beneath Superman Island. The shockwaves freed the Atomic Skull from his prison cell above and hijinks ensued!