Well flying with fire requires huge jets of flame behind you, and in that case, someone suing you because you burnt down their house in the progress. And since you're making such a deal about only a few water benders being able to heal, isn't being able to fly also very rare for a fire bender? (Now don't go seeing this as a personal attack, it isn't. Seen you reacting rather touchy to other posts so I thought I'd mention this.)Eipok Kruden said:You can fly with firebending as well. And you'd never be affected by the freezing temperatures at high altitudes. And, if you wear some kind of super awesome flying suit, you could go even faster since the G forces wouldn't kill you as your body would be protected.
PS: and even in dry, dry LA, there's plenty of water. It's just hidden very well but there's a massive amount of it in the soil. If there's plant life, there has got to be water in the soil.