I think the airlines would balk at this, since the roller won't fit entirely under the seat in front of you. Even if it will technically slide under the seat, the end will stick out into the space between your feet. Because of various FAA regulations requiring everything to be stowed for takeoff and landing, this is not allowed.
Airlines make special arrangements for strollers, baby seats, and other oddly-shaped items. But most non-runners value baby stuff more highly than they value their foam rollers. (Suckers!)
You could try showing up at the airport, walking up to a ticketing agent with a smile on your face, and asking if they could do you a favor and check it for free, since you are a poor college student. Worst case scenario is they say no and you throw it out (or give it away to an arriving passenger) at the airport.
But you would probably be better off buying a new foam roller for $25 ($30?) on the other end of your journey. If you have ITB issues, this is a really small price to pay, when the alternative is a summer of knee and/or hip pain.
(FYI, this is the best 1:30am "can't muster the strength to finish this damn paper" procrastination that I could have imagined. Keep shooting those random questions into the lestrun ether, and I'll keep allowing myself to be distracted!)