At the end of Flight of the Navigator, David time travels, creating an alternate timeline where he didn't go to Phalon{sic} for 8 years.

Lets call the David who disappeared for 8 years, David-A, and the David we see at the end of the film, David-B.

What will happen when David-A returns after 8 years?

  • Would David-B realize that David-A will arrive after 8 years?
    – user35971
    Commented Apr 16, 2016 at 2:50

1 Answer 1


My understanding from the film was that there is no alternate timeline anymore. Rather, the passage of history is now that David is removed from Earth, taken to Phaelon for eight years, experiences the process of navigating his way back from the future, and then returns to within moments of his departure. He is the only David because there is only one timeline. The David who was sent to Phaelon at the beginning of the movie was returned, with a short side-trip into what is now no longer a future.

So, in short, David is taken from the Earth and has the star charts in his head. Eight years pass by on Earth as he is taken to Phaelon, studied, and returned over the course of a few hours for him. He returns to Earth and has his adventures in the Earth of eight years in the future. He convinces Max to let him use the hazardous time-travel method, and is popped back to shortly after he left (I don't believe that it is exactly established how much time has passed here, but the reactions of his parents don't seem to indicate that he's been gone the "hours" postulated for the original trip). The David who arrives is the same one who was abducted at the beginning and was briefly in a future.

Now that I look at the timing again, there's still some ambiguity going on in that they originally say that he spent hours going to Phaelon and being tested, but he seems to have arrived earlier than that. That suggests that it wasn't all just light-speed relativity at work (probably pretty much a given since they managed to go back after eight years. Relativity does not allow time travel into the past, just a slowing or even stopping of relative time) and that there may have technically been two Davids for the period of a few hours (one on Earth and one on Phalon, but the window would have been short, and there will be no David-A arriving in 8 years because that David is the one on Earth, David-B.

  • It seems like this would be inconsistent, since when he returns to his own time he still has memories of his travels, which would include remembering a future in which everyone thought he had been missing for 8 years...where did those memories come from, if there was only one timeline and he lived his life with his family after returning to 1978? But maybe you could assume a sort of "meta-time" model like the one I suggested for Back to the Future here, then his memories would be of an "earlier" timeline in meta-time.
    – Hypnosifl
    Commented Apr 16, 2016 at 4:23
  • I probably didn't make myself entirely clear. He has all of those memories of events on an alternate "eight years in the future" timeline, but the mythology of the movie doesn't seem to suggest that that timeline still exists. I will try to explain things a bit better. Kind of a shame they never seem to have novelized this one...
    – FuzzyBoots
    Commented Apr 16, 2016 at 14:23
  • So similar to the meta-time model I mentioned, where there's a sequence of timelines but each time a new one is created, the old one ceases to exist? But that wouldn't resolve the original question, since when he arrives in 1978 it should be at a point in time just after Max had originally abducted David's younger self, so after the older David arrives there should now be two Davids and two Maxes in this version of the timeline, with the younger versions en route to Phaelon at FTL speed. Probably this was just something the writers didn't think about, or figured the audience wouldn't...
    – Hypnosifl
    Commented Apr 16, 2016 at 14:56
  • Still confused about your argument--in the original timeline David wasn't on Earth but he still existed in space for the entire 8 years, just experiencing time at a different rate from Earth. Say David was abducted at 8:00 PM July 4 1978, and in the original timeline someone saw it happen, & they watched the ship travel away with a super-telescope that could track it all the way to Phaelon. If in the new timeline David returns from the future at 8:15, wouldn't this person still be able to see the original ship in space at 8:16 and so on? Do you think they'd see the ship vanish at some point?
    – Hypnosifl
    Commented Apr 16, 2016 at 19:57
  • @Hypnosifl: Honestly? You'll basically have this problem with any form of time travel, especially when combined with trying to have near-lightspeed travel add in relativity. It's possible that sending him back in time would indeed make the ship disappear. Given my understanding of relativity (admittedly shaky), I think your super-telescope would start facing the same sort of issue "catching up" with the ship. Because your observation method would have to approach light-speed, it would take 8 years for you to observe the ship. :)
    – FuzzyBoots
    Commented Apr 16, 2016 at 20:32

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