These
birds flew like an arrow, steered like a cow, and had
a lukewarm wingbeat. An alula would have been entirely
wasted on them. Swifts are the closest modern
approximation in aerodynamic shape.
I, like Jim, am I bit confused by why you think a leading edge vortex
generator would be useless on Confuciusornis. Also, I think the
analogy with swifts is a bit strong there; given the much smaller size
of swifts and their lower wing loading, I would not consider them a
good aerodynamic model for Confuciusornis. By "steered like a cow" are
you suggesting low maneuverability, low agility, or both?