Actually I think yesterday's episode showed she's learned to glide (Going far while descending) at least seeing in ponyville confidential she couldn't even slow her fall with her wings and in the scene up to when Babs came on the train she fell to the ground slowly while flapping her wings, so she can't 'fly' yet, but she ain't a dodo as they don't glide. Plus chickens actually can fly slightly, its just their large bodies hinder their flight and dodos weren't skinnier than chickens either, so calling Scootaloo a chicken or a dodo isn't an accurate meme to me now cause she ain't fat. She actually seems slimmer than bloom and sweetie.