ssolie is correct, your planes under no condition, can they move more than 4 territories on your turn. If they were on an allied carrier then on the allies turn the carrier moves, on your turn you can move the plane 4.
When a carrier is sunk the planes can move one space. So if a carrier was in an adjacent territory or an island with an airbase yes the planes could land there. The planes could not fly to the adjacent territory then land on an island without an airbase.
BB
