My Illogical Theory
Okay, this is my illogical theory. :3
I think moves like Bounce and Fly (those sorts of Flying-type moves) will actually get more damage. I don't know, it seems like some sort of trend. Like think:
>This move's damage will increase if used in Sky Battle.
Just think - I think it could work. :O
Unless Game Freak is as illogical as my theory (I like saying the word illogical. :3) then Gravity has a 99.99% it will probably have a disadvantage, but there is also a 99.99999% chance that I'm wrong. Just think of the possibilities. xD
Also, moves that would otherwise be affected by Gravity would probably not work since they involve being up in the air (which really only affects moves like Jump Kick and Hi Jump Kick, which really isn't learnt by any Levitating Flying types)
I like my theories. Just letting you know since this is really long. ;3
Also - I can't believe this hasn't been mentioned but I think Sleep is negated. I mean, it might not be made due to Game Freak's logical issues but it might be something to think about.
And nearly lastly, the effects of the Air Balloon and the Iron Ball will be negated. (Or in that case, anything heavy.) :O
And (final one) - Ingrain will not work. There. Done. :D
I don't think I've helped since it helped, but...
I hope my theories enhanced your logical ideas in producing the negative and positive verdicts of certain strategies in the new Generation Six Poketto Monsutaa Ekkusu to Wai games, which have been romanized to Pokemon X and Y. :)