The other day I was watching Man of Steel, and getting seriously pissed off about the whole being able to fly on Earth thing, but needing this four-winged bugblatter beast to fly on Krypton.
According to Jor-El, it's because Kryptonian cells can drink up yellow radiation like it's a magic potion or something - which is just flat out fairy tale bullshit - but also because the Earth's atmosphere is more nourishing. What the...?
Yo, Jor. Premier scientist of Krypton and all Kryptonians. Food is nourishing. Not air. FOOD.
Ok, you're not from around here, and your crappy telescopes only show the Earth as a shiny, gray ball of mud. I get it. You don't have a lot work with, so here's some bona-fide info about planet Earth, from an actual Earth man.
Earth air does two things. It oxygenates the blood, and it keeps it from boiling. That's it. There is no nourishment in air. That's what food is for. Food, Air. Food, Air. Two separate things. One provides nourishment, the other provides oxygen. This is common knowledge on Earth. Don't you guys have food and air on Krypton? Come on, man. You're supposed to be a scientist.
There is one more reason that Jor-El gives, that at least isn't completely retarded, which could actually maybe kinda sorta explain the flying thing. It has to do with the Earth having weaker gravity than Krypton. Here's the theory. In order to withstand the crushing gravity of Krypton, Kryptonians had to evolve anti-gravity organs, and on Earth, those anti-gravity organs don't have to fight against the crushing gravity of Krypton, so you can just use 'em to fly around.
Ok, that's it. Just had to get that off my chest.