We flew from Manchester NH last Jan/Feb. It's about 3 hrs beyond Bangor, but Southwest flies from there, why we were looking at it in the first place. We ended up flying Continental b/c we could book further ahead, assigned seating, for not much more than a ding! We're looking again and Continental again has great rates, though we're also looking at SW. Manchester airport was great, it's small but has all teh facilities you'd want, clean, we were on time... The drive was great too, we had clear, dry road all the way. Of course you're taking your chances travelling in the winter, but we'd do it again in a heartbeat. (We drove from New Glasgow last year but have since moved to Halifax--virtually the same distance.) Got a good rate on a park and fly at one of the Holiday Inns in Manchester, also a nice, clean, convenient hotel.
Oh, we did look at Bangor, but Matt Molloy of the Cheiftains owns a pub in Manchester, and we're determined to check it out on the way through--if it's anything like his pub in Westport Ireland, it'll be more than worth the detour!