As I understand, limited jump seat agreements with other airlines. I know they are trying. Unless you live within their Northeast route structure, it is very hard to commute and keep to their schedule.
Boston Maine Airways is a Part 121 airline. Their only base for now is PSM (Portsmouth, NH). Other than Boston Maine and Pan Am, no other scheduled service into PSM. Nearest major airport is BOS which has direct bus service from PSM to Logan about 14 times per day.
Best to have a car and a crashpad in the local PSM area while working for them. I'll try to find out what if any jumpseat agreements they have.