Actually, from a lore stand point (the most important stand point) flying is incredibly rare and the latest show of flying was a flying potion created within the Oblivion city, Umbriel. That potion was an extremely powerful one. Levitation isn't common place at all and all the instances of levitation, were not very high and not far. The levitation in Daggerfall and Morrowind was a bit much and dipped into godhood, which is not good from a lore or game standpoint.
I recognize the rarity of true flight on Nirn. However, Levitation was at least fairly common, especially with, but not at all limited to, the Telvanni... Many of whom fled to Skyrim after the Minstry fell.
So sure. Flight almost never happened. That is until Anna?g cracked the recipe. She even lists the ingredients. The secret one that she found in Umbriel's kitchens was Ichor of a Winged Twilight. That's a real thing. Well, within TES lore anyhow. I mean to say, I've fought Winged Twilights, so have you. And there is even more them and their ichor in the Post-Oblivion Crisis world. The others were common ingredients, typically used to make levitation potions. So from the MOST important standpoint, flight potions have existed for 150 years. Improving upon Levitation that has existed even longer.... In the lore.
Also... Dragons. The Dovahkiin will be granted the power of the dragons. I don't know about all twenty but I have to say... Fire Breathing and Flight are likely to be in the top 5 of any list, especially one that large.
According to King Edward, Part XII:
"Moraelyn asked with a smile, 'All right then, I've always wanted to know this - considering the shape of your mouth and teeth, how do dragons manage to speak the humanoid languages so clearly?'
Akatosh paused, and then carefully responded, 'Why, in much the same way that we can fly, even though our wings are not naturally strong enough to support such heavy torsos.'"