If these are alien craft, maybe they're not flying through space ... or even warping space (Alcubierre-ish) but just leaping through it. Like stepping through a

If these are alien craft, maybe they're not flying through space ... or even warping space (Alcubierre-ish) but just leaping through it. Like stepping through a curtain. If our whole understanding of space is wrong, then they'd be asking themselves "why are they making it so hard?".