We're using lithium-ion batteries (for now), so charging is like any electric car. As long as you have the power to fast charge it, you can do a full batter in ~45 mins.

That's max range (=180 miles) at 45 min charge. So let's say we're doing 90 mile missions between the islands of Hawaii, you only drain half the battery, so charge time is only ~20-25 mins - which is how long it takes passenger to unboard and board anyways!