I am David Trivias

In the belly of the ship, David lights a match. In one shot, the match is burnt almost in half. In the next shot, it is a newly-lit match.In the window of the Italian bookstore, the book on display next to the book the protagonist is looking at, is clearly, "Cieli e mari: le grandi crociere degli idrovolanti italiani (1925-1933) / Ranieri Cupini". The first edition by Mursia was in 1973, long after the events in the movie.

When David is about to board the flight to meet his mother, we can see the tail of a modern airliner that is taxiing in the background.The radar installation at the airport where David departs is clearly more modern than one that would appear in 1952.