I write and draw a variety of fantasy creatures, from angels and demons and the in-between, winged humanoids of all shapes. I've picked up a few reference links along the way, which I'll share in this post, and every time I run into other resources for drawing wings or people with wings, I'll drop the link here too.
Even if you're not into art, there's a lot of knowledge of flight and wing design that can be useful to people writing about flying characters, whether it's a dragon or a demigods.
Slim's Bird Wings and Flight Tutorial
Slim's Bird Faces Tutorial
Slim's Straight-Billed Bird Tutorial
Thoughts on Wings by AuroraCarina-chan
CactusArt's Bird Wing Tutorial
Driany's Wing Tutorial (Anime style with some wonky anatomy)
WindFalcon's Realistic Wing Tutorial
Nambroth's Realistic Bird Wings
Nomers-Sushi's Basic Wing Tutorial
How to Animate a Bird In Flight (Though it's focussed on animation, it's a great resource for anyone interested in the movement behind flight.)
Reference Images & Videos
Slater Museum Wing Collection
Wing References by AuroraCarina-chan
SenshiStock's Wing Stock Images
The Origin Of Flight
Got something that you think belongs on this list? Anything's welcome, from cool images (with a source) to movies and documentaries. Drop me a comment!