1 Jamie: Okay, set the time machine for the year 2000 and see if they really do have flying cars?
2 Adam: No, they might not actually have them by then. Besides testing the myth, we need to see what it actually takes to recreate the circumstances of the myth.
3 Jamie: Good idea. How will we do that?
4 Adam: Let's go to... say, 2009. Then they're bound to have flying cars, and we can just check how many years earlier they became common.

See, this comic is more realistic than many pieces of science fiction. At least we admit that there might be a time in the future where we might not all have flying cars yet.

Obligatory TV Tropes link. Don't say I didn't warn you this time.

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2022-11-12 Rerun commentary: This is one thing that will never date any work of fiction. You can have people say that flying cars are 15 years in the future and it will feel right for any time period.