I've been looking into flying a bit lately and like the part on flying stuff in TME and then I stumbled upon this image on the internets. It's from the TV series Da Vinci's Demons, which I have to admit I've never seen and barely remember hearing about when it was made some 5 years ago.
But never mind the winged sandals or the flying carpet.
This is obviously the best flying magical item one can make.
I guess a little shape/material bonus for the wing shape would be in it's place and then base it off of Vessel of the Clouds (TME pg. 112) and just drop the Touch and Size modifiers for a ReHe 20 effect.
I would think the classics so Wings strapped to arms (Like Daedalus and I think Wayland), winged sandals (Hermes) and flying carpets. I am sure there must be some flying items from Norse or other mythologies I can't think of.
I think De Vinci's Ornithropters or complicated gliders are a bit anachronistic. Although I can see a Veritius making wings like those in the picture .
The other route I can see is winged animals so pegasi or similar
Arke, the messenger of the Titans (as opposed to her sister Iris, the messenger of the gods), lost her wings after the Titanomachia, which eventually came into the possession of Achilles via his mother Thetis.
Shapechanging into a bird is one of the few ways to fly using only the core rulebook, is easier than using CrAu, and has plenty of mythological precedent, so I suspect that’s a common means of flight.
Witches fly around on brooms and in cauldrons. Snooty houses might look down on such a “hedge magic” tradition, but houses and tribunals with a good relationship with hedge wizards (Ex Misc, Provençal, for example) might embrace it.
Being carried by a giant bird is somewhat fashionable in the Middle Ages—both Dante and Chaucer do it. Transforming your familiar to a size large enough to carry you is not terribly difficult.
ArM 5 guideline for changing into a bird is base 20.
Wings of the Soaring wind, the CrAu flying spell, has base 5 +1 magnitude for Rego requisite and +2 magnitudes for highly unnatural winds, so that also turns out at level 20 before we start adding for range and range and touch.
But shapeshanging does have one big advantage, the mundanes will not see magi with wings, or on brooms or magic carpets zipping in and out of the covenant.
ReCo flying however is base 15.
Thor rides across the sky in a chariot pulled by goats. I think it is the goats that make it fly but it might also be the chariot. Either way, hermetically speaking a flying chariot is probably easier to find/make than a flying goat (or other beast). There are also some stories about Freya riding in a flying chariot pulled by giant cats (maybe cougars? maybe just giant cats unspecifically) again I am not sure whether it is the chariot or the animals that cause it to fly. Lots of norse myths about people wearing animal skins to turn into animals, many birds in particular. These hides can often be loaned out, suggesting that they are, in ArM terms, enchanted items rather than casting foci.