In the previous post I quoted an article that made the point:
"The cladistic analysis of the Boreaspidids may simply not be as accurate as the Kiaeraspidid analysis. The j/k/l/m cluster, rather than being a basal group, may actually be an advanced one, like the s/t grouping, and it only appears primitive (perhaps through degeneration or loss of characteristics)."
This is an uncanny parallel to exactly the point that I have been making about birds.
I have been pointing out that the flightless birds (Alvarezsauridae etc) which had lost their flying-bird characteristics, developed from the flying birds, and that the fossil record indicates that the flying birds came before the flightless birds.
The standard dino-to-bird cladograms have it backwards.