Throughout the 1960s and 1970s, the airport was served by Northeast Airlines with the CV-240, DC-9, and FH-227. Delta Air Lines absorbed Northeast in 1972 and continued to serve the airport with the DC-9 until 1978, then 727-200s until 1980 when it discontinued service at Manchester. In the mid-1980s, airlines once again started offering jet service out of Manchester. United Airlines inaugurated service at Manchester in 1983 with two daily flights to Chicago–O'Hare. This was part of their 50 States campaign, which positioned United as the only carrier to serve all 50 states with mainline service. The Boeing 727 and Boeing 737 were initially used on the Chicago flights, which would often make intermediate stops in cities like Providence, Albany, Syracuse, and Burlington, to pick up or drop off passengers. Manchester was also a "tag-on" for United flights heading from Bangor and Portland, Maine, to Chicago, but the carrier no longer serves either city with mainline aircraft.