The Boeing 727, put into service in 1963, had the distinction of a rear doorway with stairs that could be lowered so that passengers could embark and disembark at rural airports which did not have their own airstairs. As initially designed, this door could be opened even whilst in flight.
In 1971, the highjacker known as DB Cooper famously used the rear door to make his parachute escape mid-flight. According to wikipedia, the CIA also used this feature to drop passengers and supplies mid-flight.
In the wake of the DB Cooper incident and other hijackings, the FAA mandated in 1972 that cooper vanes to be installed to prevent the opening of the rear door while in flight.
Does this make the pre-cooper 727 the last passenger airliner whose doors (either passenger or cargo) could be normally opened while in flight?
Animated image from wikipedia and cc.