to me that just makes no sense - I mean there’s probably some kind of math-evaluation that said so, but… uh…
slower compared to what? It’s not like you can take a stopwatch and look how long a second feels.
Time “now” isn’t fixed either - move closer to a black hole or just move faster and your time becomes slower - COMPARED TO THE REMAINING UNIVERSE.
But you’ll only notice when you return and compare clocks. Back then, when everything was faster, there wasn’t something to compare to? So nothing was faster?
and even if they were to build it and sell it for 100K€ per airplane (they never will)
…it’s still ridiculously stupid