So, MY Story is that NIMITZ is on patrol, her last one, but still a hot patrol, near Pakistan. When an A/C of unknown type, (Like X-Wing unknown-type), lands on the carrier. The pilot is from the .... Future!!!
He explains that NIMITZ will Not retire, but instead gets involved in holding off 'unknown country' (pilot will not divulge info) from wiping out "His country" from being nuked, but in doing so see ..... NIMITZ get nuked instead before entering our timeline.
But, there is a way that he could stop it from happening, with the special weapon that he was about to carry on a one-way-trip.
Haven't gotten beyond that idea, but That is what they should do as a sequel.
P.S. Strangely, Martin Sheen character is on that film again, talking to That pilot, who he could/could not see, later on at the end of the movie......