Hi,

While the flight option may be a good one theoretically, it probably won't be the best one in practice. Mainly because you don't factor in the cost of taking a taxicab or T ride from Harvard Square to Logan (to and from) and assuming the commuting cost is negligible on your end in DC. Also, there's certainly issues being cramped on a commuter plane with loads of people (especially if you class was on a Monday or Thursday).

I would definitely consider buying up the train tickets if you can afford the time to be on the train. I think when you factor in all the commuting costs (You could be at North Station which is definitely closer than Logan) and the benefits, it may save you the headache. Also, you can do some work on the train or watch a movie...and it's more comfortable.

Good luck!