This one looks tough because it doesn't list any single carrier between those two cities. it does show manchester to boston on some outfit called Precision using beech 99, piper navajos, and twin otters. Also Bar harbor used Convairs on that route. If that's the case it probably connected with eastern at BOS, but then eastern would have required additional connections in Laguardia, Charlotte, or National. Piedmont is the only carrier shown with non-stops between Boston and Greensboro using a 727-200. Sorry I wasn't much help. By the way, EAL used DC9's, Airbus 300's, and 727's in their frequencies. Any more questions just ask.