God it's gotten worse. Last time I looked they had flights to PHL and DTW.
As it is now there is fierce competition for bus service from Ithaca to NYC (budget to various grades of premium) and I find it almost unimaginable that I'd fly to NYC to get to NYC because flying to JFK or atrocious EWR (never once made a transfer at EWR that didn't involve re-entering the secure zone) wouldn't save time to get to Midtown.
If you try to take the bus in the other direction you find you can't get from here to there. A friend of mine who used to ride the bus through Canada to get to the Detroit suburbs now takes the bus up to Syracuse, then takes Amtrak and gets out at 4am. On the way back one time there was no room on the bus although he paid for a ticket ahead of time.
The real significance of the regional airport is that it connects to a hub that goes everywhere. As it is if I have to fly somewhere I'll probably have to go up to SYR where at least I can fly on Jetblue and know I'm flying on an Airbus.
ITH used to get
https://en.wikipedia.org/wiki/De_Havilland_Canada_Dash_8
which I really enjoyed flying in, but they got replaced with 50-seat regional jets because regional jets are less likely to break down at a small airport requiring a crew to travel two hours to repair them.
As it is, academics at Cornell and Ithaca College will struggle to bring in speakers and it's just one more bit of "stave the countryside" that will drive knowledge workers to go to blue cities where their votes don't count -- it's how you hand the next election to a Demagogue.