As for those ART segments:

This is before any of the express carriers were in existence (except for Allegheny Commuter, which has already been ruled out) so it's time to think of small carriers in upstate New York. I can think of several in the six New England states, but Empire was the only one that came to mind for New York. EXCEPT ... I just saw something totally unrelated that reminded me of Colgan Air. So:

SYR-ART and ART-SYR, 9L, SF3 (since the B99 has already been ruled out)