The asymmetrical vanes of the remiges and rectrices of _Archaeopteryx_ suggest some kind of aerial capability. But not necessarily powered flight, because _Microraptor_ has them too.
Of course, the only argument against *Microraptor* being a powered flier is the same one that holds for *Archaeopteryx* and *Confuciusornis*: its shoulder joint.
However, some flightless birds retain asymmetrical vanes (e.g., flightless grebes)
Oho. Reference, please?