The 747 of the title is not the well-known plane. It in fact refers to a Tardis-like craft that can jump through time and space. It was/is/will be named after the well-known Boeing airliner.
The jokey phrase "What is the past tense of 'to be' on a 747?" comes about because (a) everyone had a 747. It was the most popular travel box of its time. (b) because, when it was in vogue, time travellers were still grappling with ways of talking to each other about complex time relationships.
In The Hitchhikers Guide to the Galaxy, Douglas Adams writes about unusual English verb tenses that are necessary with regard to time travel. I suspect his intention was mostly to be humorous. However, I am wondering whether, when time-travel is customary, we will need such grammar in order to be comprehensible.
My Examples
Q: Where will you be tomorrow? (or perhaps, When will you be tomorrow?)
A: I will be in yesterday tomorrow. I'm travelling back there to locate my lost briefcase.
Q: Where did you go on your holidays last year?
A: I went to next week.
Q: Do you mean that last year, you went one week into the then future?
A: No, I literally mean that, back then, I went to what is now for us next week. By the way I saw/will see you there!
Question
Are there limitations to the English language (especially verb-tenses) in a world where time-travel is a common occurrence?
Attribution The rather odd question at the beginning of the title was inspired by and came directly from a comment by @L.Dutch - Reinstate Monica, regarding a previous question of mine. What if the world is not real? No I don't mean a simulation
The comment made me think and gave rise to this question.