Glossary to help making the rulebook easier to read:
A round is “each nations has their turn to play”
A turn is “This nations has its turn to play”.
So, the UK player moving all its pieces is “a turn”.
When an aircraft leaves a coastal territory or island, does it cost one point to move into the sea zone adjacent to the territory/island? for example, If a plane leaves Japan on the pacific map, does it cost one movement point to move in to sea zone 6? The way I read the rules, it does.
Yes, it does cost a movement point.