Only an hour from Dexter's, this is the closest airport with good flight options and a good car rental situation. It's our preferred airport - direct flights to Raleigh-Durham, usually on time, none of the lines/chaos of Logan. Looks like they have flights to Minneapolis with 1 stop.
At 1h50m from Dexter's, this is Vermont's biggest airport. It's small but mighty. Direct flights to MSP and RDU. Car rental facility at the airport and your forced to drive through Vermont and Caitlin's hometown (ask her for recommendations on where to stop along the way).
At 1h50m from Dexter's Inn, it's New England's biggest airport. It has a big car rental facility and the Dartmouth Coach Bus will bring you directly from the terminal to a park and ride that's 15 minutes from Dexter's. However, it's also a bit notorious for long security lines and delays. Leave plenty of time.
This bus goes directly from Boston Logan Airport and Boston's South Station to a park and ride in New London, NH, only 15 minutes from Dexter's. It continues on to Hanover, NH, less than a mile from Caitlin's hometown of Norwich, VT. The bus goes multiple times a day and is clean, reliable, and wifi-equipped.
At 1h40m from Dexter's, this smaller airport in NH has direct flights to Raleigh-Durham on Breeze and car rentals available.