Everything about this video is to be applauded.
Click to see (about a half-minute playtime).
The Pterosaur Heresies
There's something very wrong with our pterosaurs.
Everything about this video is to be applauded.
Click to see (about a half-minute playtime).
The Pterosaur Heresies 
Makes you wonder whether the ratites descended from flying ancestors or whether their ‘wings’ were only ever stabilisers for running ??? ;-)
Interesting thought. The LRT indicates Rhynchotus. a tinamou, was basal. It can fly, but prefers walking and running. Megapodius is similar. Chicks can fly shortly after hatching. To my eye Archaeornithura looks like a long-legged capable flyer. Phylogenetic bracketing can be so helpful for questions like this.
It was just a wild thought :-)
However the deeper issue is to explain what kind of forelimb was preadapted to evolve to a wing. What function(s) could large stiff feathers serve on a not-quite-yet-wing? Display? Stabilisers while fast running?? Gliding is usually suggested, but you’re not going to launch yourself into space unless you *already* have enough wing surface to prevent a crash-landing …
With dinosaurs, as with pterosaurs, the locked down coracoids suggest flapping, even frantic flapping, before flying. Dial’s work suggests the same. I agree with you that gliding is not what basal birds do with their wings. Frantic flapping keeps predators from attacking and provides thrust for extra speed when needed. For display static feathers are the thing, not flapping. So perhaps a dual role for feathers prior to flight?
Also see :
The short, but still locked down coracoids of Microraptor suggest to my eye that Microraptor could flap, but not with much power. IMHO this animation would have been more realistic with some frantic, but underpowered flapping. The powerless gliding seems an overreach. Your thoughts?