Some more tidbits concerning Frontier Airlines in the 1950s:


More promotional material, showing the routes as they expanded into N. Dakota:








Hustling the pax onto the plane, ca. 1950s:








A 1963 sectional showing the old Stapleton Airport... Denver is still Frontier's home base, but the old airport is long gone. I've been using KDEN in the sim... it's not the same, but it'll do.





Exterior and interior views of the old terminal:




Wish I knew more about this gorgeous Stearman done up in Frontier colors- I guess it was flown around Denver for promotional purposes. Note the smoke system and upside-down logo... and the "eight-ball" wheel covers!! Fantastic!
If they offered scheduled service with this beauty, I'd imagine the "fasten seatbelts" advisory was not to be taken lightly...