Indeed. Actually you need the errata in case you own an older/outdated print of the second edition rulebook. But in that case you are fine with updating the rulebook itself.
Sometimes it can get a little confusing in island sea zones which units are in the sea zone and which are on the island. The statement is intended to make sure the attacker indicates which air units are which, since they can in many cases get to either space.
on a related note, I certanly hope the UK is one territory in Europe 1940. So they can scramble to protect it just as japan does
That would mean that Britain could only touch one sea zone (unless they want to make an exception rule) and would almost completely rule out any possibility of a German naval attack or Sea Lion attack.
It would probably make it too easy to build up and invasion force to clobber Germany since the US can just stack up planes in England and they can defend the entire Brit fleet as well.