Which is the least of it. There is anywhere from 1.5 to two hours on either side. And the additional $200 each way, given the distance of the airports from the city center.
I fly to Montreal once a year from Boston and 1.5-2 hours on either side is a gross exaggeration. The Air Canada flights to Montreal have a dedicated security line at BOS and it takes roughly 7 minutes to get through it. I've also never waited more than 45 minutes for customs in Canada. On the way back, US customs take about 20 minutes thanks to automated terminals they have installed.
You don't get to the airport an hour early? It doesn't take you a half hour to drive to the airport and park? No idea, I've never flown out of Boston, maybe Logan's closer to town than JFK is in NY. I'm just saying, because from my place in Manhattan getting to Penn is literally a five minute shot up 6th Ave.
From the equivalent location in Boston (Beacon Hill) your a 15 minute or less Uber ride away from the gate at BOS. For flights that have dedicated security lines or if I get pre-check I'd leave downtown Boston 1 hour and 15 minutes before takeoff. I've only been bitten by this once in the last few years, in which case you can find an airline employee to get you through the security line ASAP.
However, even if you want to get to the airport early, it's not like that time is wasted. These days I would say relaxing in the airport is just as nice as relaxing in a train car: http://www.nytimes.com/2014/12/08/nyregion/improving-ground-.... The last time I was at LGA early I had a huge table to myself and the person I was with, and the table had an iPad I could use to order food and drinks.
Uh, it does not cost $200 to get from Manhattan to LGA. It doesn't cost $100 to get from Manhattan to LGA, there and back. It's even cheaper if you fly from EWR; you can just take the train from Penn Station.
