Flight via summoned planetoid? Mutants & Masterminds does it so that you go at space travel speeds only when outside atmosphere, which makes sense.
As for rebinding, I'm thinking you could start drawing the sigil and the pact making process before the previous binding wears off, somebody more familiar with binders chip in on if that is possible?
Alternatively if moving at space travel speeds, you get time dilation so your bind lasts longer.