Corrected entry: If the woman from the village is pregnant, then how come she maintains the same weight throughout the later part of the movie?
Corrected entry: Costner finds the old mail van with the skeleton inside, still wearing its old uniform. He then takes and wears this outfit. Surely if the original postman had died in the truck still wearing these clothes then his corpse would have rotted away inside the uniform, infestations of maggots, disintegrating flesh, and bloating and bursting innards would have ruined the uniform beyond belief. But not only is it clean and fragrant enough for Costner to wear straight away, it's also dapper enough to get him laid by the couple wanting a baby.
Corrected entry: General Bethlehem says he was a salesman before the war (he sold copy machines and stuff like that). The General is about the same age as the Postman. At the beginning of the movie we learn that the Postman was still a child during the war, so the General must have been a child, too. How could he have been a salesman before the war?
Corrected entry: The film is based after some war that took place many years in the past. In the film you learn that Kevin Costner was a little kid during the war. He is at least in his late 40's in the movie, so, the war had to have taken place over 30 years from the time period of the movie. But, later on, he meets Tom Petty, who plays himself, and says 'I know you, you were famous". But, Tom hasn't aged a bit.