Just before the time jump to 1975, the sound of the TARDIS can be heard just before the Waverider jumps.
Rip mentions "Per Degaton" who is a classic time traveling villain from the golden age of comics.
Arthur Darvill plays Rip Hunter, a time traveler. Previously, he played a companion to a time traveler in the BBC series Doctor Who (2005). Also, companions to the Doctor were River Song (Alex Kingston) and Captain Jack Harkness (John Barrowman). Alex Kingston (as Dinah Lance) and John Barrowman (as Malcolm Merlyn) have both starred in Arrow (2012) which belongs to the same world as Legends of Tomorrow.
While in 1975 team members are seen watching an episode of Welcome Back, Kotter (1975). DC Comics actually published a Welcome Back Kotter comic book series in 1976-78.
Rip Hunter was originally identified by Eobard Thawne, in The Flash: Fast Enough, as the creator of the first successful time machine.