The Brown family visit 2091, in which they learn that the McFly family legacy has been immortalised in the McFly Space Cruises, in which Marty's great-granddaughter Marta McFly is a Captain.
When Jules and Verne fly the train through the big Courthouse billboard (the one that says "Historic Hill Valley"), the train flies directly through the clock. The hole is the same size as the clock. Yet in the next shot the hole has taken up half the Courthouse!
When Jules and Verne give the newspaper to the security guards, the front page with the story about the disaster is now in the middle of the paper.
Upon hearing about the McFly Space Center in 2091:
Verne: Vice Principal Strickland always said the McFlys were a waste of space!
Ziff mentions his "Grandpa Griff" - and at the end of the episode we see Grandpa Griff Tannen - the same Griff Tannen who appears in Back to the Future Part II!
Clara makes a reference to when she and Doc first kissed in Back to the Future Part III.
Marty does not appear in this episode, however an impersonator of him is in 2091, playing to a crowd on the cruise ship. It appears that Marty's rock music is still popular by the late 21st century!
Verne mentions Vice-Principal Strickland, who appeared in Back to the Future and Back to the Future Part II (played by James Tolkan).
Debuted May 24, 2003 on the Fox Box.
This is the only episode in the series where people time travel into the future - in this episode they go to 2091.