More from this 2011 study:
"The timing and sequence of events that led to the origin and subsequent evolution of flapping flight in birds remains an important unanswered question in vertebrate evolutionary biology."
The question is "unanswered". That is quite an admission.
The dino to bird enthusiasts themselves acknowledge that on the most important question they have no idea.
They cannot even figure out a story to explain how a purported unknown, unfound dinosaur lineage somehow developed wings and feathers and became birds.
It is an absurd idea. And for most of history it has been recognized as absurd.