@Artaxiad:

How many territories can a unit take over in one move?I.e. Can a bomber take over 6 because it can move 6?Or is it that a unit can only capture 1 territory a turn?

Air units cannot capture a territory (They must land in a territory owned by you at the start of the turn as well)

Tanks can “blitz” through an unnoccupied enemy territory and move on to a 2nd territory and thus capture both in the same turn.

All other ground units only move one space per turn anyway, so obviously One for them.