Can a Main Contribute to Empire/Fed Defence? (Little Upsilon)

I know the main can't attack another player's country but are its defences used to aid another country in the same empire and does it contribute to federation fefences as well?

I've been absent for a while and I'm curious about this particular point.

Thanks for any help in advance.

Fedair from main - yes

Thanks for replying, that's super, just what I wanted the answer to be as well.

I've already asked that question myself green paws such as Josias, but it's the range of the helicopers and interceptors you need to worry about, make sure once you conquer other countries they're within the range of about 1000 miles or Km of the defensive air force.