My game's flying warden does it on channeled blasts of wind that are thematically similar to Storm of the X-Men. The ring created by his Superb Lore and multiple enchanted item slots grants him the ability to move in 3 dimensions for a scene using his Lore to achieve dramatic effects such as clearing Barriers, evading Blocks, and using the spell to dodge. He can activate this for "a scene" and do so up to three times per day, but each additional use (per enchanted items) inflicts stress.
It is certainly possible to manipulate gravity as presented by the case files. Earth magic covers it on the grand sense, so I don't see why a Focused Practitioner specializing in earth magic or gravity couldn't exist. If you want to handle flight with quick spells evocation will permit the caster straight line direct force effects. Change gravity to levitate for a few exchanges, perhaps, or even create a quick shift under the caster to propel him upward into the air, but without extra shifts being spent on time an control these are one-time efforts that each cost one mental stress minimum.
Due to the already mentioned effect in Changes it is meet to say that you can affect only yourself with gravity alterations, and do not necessarily have to be walking on a column or raised energy.
Now I'm fuzzy on thaumaturgy, but trying to wrap my head around it. I can't give you the number of shifts and such that you would need, but there's quite a few to create an effect that is going to be on the person for long enough to have direct control over movement long term. The idea of creating a ritual to work this is possible, but again the effort involved is staggering due to the amount of shifts you need to cover time and other features.
If you want to use spellcasting to model flight, one of the best pieces of advice I received in my own query (
http://www.jimbutcheronline.com/bb/index.php/topic,20386.0.html) was to ensure the spellcaster took an aspect that spoke directly to his having studied flight in the past. Hands down, the easiest way to do this is to have the character take a modified version of Wings, call it whatever works for the character, have it cost -1 like Wings, but require the aspect. At the very least the aspect will be useful in the application of said flight. While Ophidimancer is right that Wings specifies actual wings, various other commentaries indicate to me that it's there because it just fits there. I have no problem simply creating a new power that does exactly the same thing and calling it something else.