As far as I remember Globespan was the main business that ran north American charters from Prestwick in the 1970s and 80s. They used a lot of Laker aircraft and eventually did a huge amount of business on Laker's scheduled services to New York, Miami and LA from Prestwick.
Aircraft understood to be 142 seat Boeing 737-300s operated by Channel Express.
Certainly not a fly by night operation .... unless Chanex forget to unload the freight !!
Globespan