Well, evocation has the extremely bad side effect, that it is more akin to a rocket jump than actual flight. Sure you can push yourself with enough force to fly up a 50 floor skyscraper, but that should be enough force to do some nasty damage (if you like, I can calculate that for you later.
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Not to mention that you need to land somehow, and depending on how your trajectory was, you will just smash into the ground.
There is another thing that sort of makes using evocation for movement rather complicated, and that's the fact that there is simply not a good rule for moving someone in a conflict, other than a grapple and running with athletics.
Now Thaumaturgy is another deal altogether. With thaumaturgy, we have the ability to get us access to temporary upgrades, and that's the most elegant solution to this and similar problems. What you do is a ritual to take yourself out. That requires 5 shifts of power, since you will have at the most a stress track of 4 boxes, and need one more to take yourself out. Since it is self inflicted, the catch for any toughness powers can be seen as satisfied and you wouldn't take any consequences to keep yourself from being taken out, either. Once you have yourself taken out, you can dictate the taken out result, in this case it would be growing wings or controlling a stream of air or using fire magic to fly on jets of fire from your outstretched hands and feet like Iron Man (only without the suit). In any case, you can spend a Fate point to buy the "Wings" power for 1 scene, and you can pretty much ignore any other numbers afterwards.
If you have enough time to prepare yourself, you could even go on a quest to get an ingredient like a gryphon's feather or something similarly rare. You could then use the free tag on that aspect instead of a fate point to buy the power. However, if you do so, you should make sure the aspect you use for a spell like this matters. If you allow any old aspect to be tagged for this, it will become pretty meaningless.
