Even with Azula's stamina, flight is impossible for anymore than a minute without the comet. She could "hover" slowly, but high speed, high altitude flight would require generating fire of such immense proportions to be in any way sensible at all that it would drain even Ozai in less than maybe three minutes. And even then, they wouldn't be able to manevuer very well due to the limitations, so the idea of firebenders flying is not only bollocks, but it's retarded.
And there is an "Avatar Level Bending", in which bending is more powerful and there are less limitations to it. Aang is the only earthbender to bend in that way that I can remember. Other ranged earthbending attacks are waves of earth or launched chunks of it that shoot out of the ground. If it's in the air, even Toph has to physically touch the rock to manipulate it (Which is why she punches the rock in "The Blind Bandit" to destroy it)
And bloodbending outside the full moon is the dumbest idea I've ever heard. If you want to throw out any fair fight at any time at all with anyone, then bloodbending it is. But if the creators ever start going bat**** with the special abilities and other abilities of bending (Like Toph metalbending at a distance) I am done watching the show.