That territory is considered full-friendly after you captured it during your turn.
So now that its after your turn, its defiantly friendly to the point where you can land planes there.
tl:dr Yes
I think you meant to say “definitely”
The rulebook says that the US can declare war on japan in a turn that japan has attacked a Allied territory (not including china.) so, can they declare war on japan right in US1??
If Japan declares war on an Allied power other than China in its first turn, the US can go to war on its first turn.
See the FAQ for important corrections to the poltical rules.
yeah, its my mistake. the rulebook says that the US gets their 40 ipc boost in the turn after a japanse attack on a allied territory. China is not included