Papua New Guinea press reports say more than 40 youths overpowered security at Kundiawa airport last week and rushed onto the prime minister's chartered aircraft in the hope of a free ride.
The Post-Courier says local youths wrongly assumed the flight was about to take off because some politicians had boarded the parked aircraft to use the toilet.
The Air Niugini Dash-8 aircraft had been flown to the highland town to return the late Chimbu Governor Father Louis Ambane.
Chartered flights in PNG are often considered fair game for a free ride.
Police had to remove the youths from the aircraft, which later flew the prime minister, Sir Michael Somare, and his delegation back to Port Moresby.