A b&w movie foom maybe the 1940's,I just remember the end where the crew and passengers are trying to leave the jungle in their fixed plane,and it is as light as possible'as they threw out everything inside;however 2 people cannot go because of the plane is still overweight.An older couple stay behind to save everyone else,and headhunters are near.The Captain gives the couple a pistol before taking off.. there are only 2 bullets in it,enough for the old gent and his wife,before the savages get them.

Five Came Back (http://en.wikipedia.org/wiki/Five_Came_Back) or the remake Back from Eternity (http://en.wikipedia.org/wiki/Back_from_Eternity)