Neither the drawing nor the blurb on Wikipedia nor the Pan Am page say so, but I will bet money that the trip used my beloved Constellations.

Transcript:

Mr and Mrs Bugg smile out from the cockpit of a propeller aircraft, which, oddly, is not rocking antennae. Their headsets and mics are a nice, authentic touch, and cute as fuck.

The text reads: “Janubug 6, 1947: Pan Ameribug Airlines schedules the first flight around the world.”