Trivia: As Sallah leaves Indiana's place, he can be heard singing the same song that he sings in Raiders of the Lost Ark (when Marion gives him a thank-you kiss).
Trivia: When we see Indy watching television in his apartment, there is a painting on the wall. This is a painting of the magical "Leap of Faith" bridge, which was seen in the climax of Indiana Jones and the Last Crusade (1989).
Trivia: SPOILER: The movie reveals that Indy and Marion's son, Mutt, was killed while serving in Vietnam. Shia LeBeouf, who played Mutt in Indiana Jones and the Kingdom of the Crystal Skull, has been vocal about his dissatisfaction with his performance in the film, much to the chagrin of both Harrison Ford and Steven Spielberg. That, coupled with the negative fan reception of his character/performance, are likely the reasons that LeBeouf did not return for this film.
Trivia: When Indy pulls the Nazi guard off the edge of the train, the guard lets out a Wilhelm scream.
Trivia: This is the first movie in the Indiana Jones series not directed by Steven Spielberg, nor with a story written by George Lucas.
Answer: There is a bit of dialogue en route to the airport when Voller sets the instrument that says, "the first hand sets the destination," as in the time you want to travel back to. This would make the device completely absurd in principle if true (that's why I wanted to mark it as a plot hole/stupidity). Since it's supposed not to open portals but just detect them, it can't be that there are infinite portals for every moment in time you can choose to go back to (and they even close). The sky, while vast, is not infinite. We then find out that it is a trick since it is set to actually bring you to just one destination, but they don't know it yet.
Sammo ★