Can Rebel Alliance Snowspeeder Launch Bay affect vehicles outside combat?
So far all my searching of forums has yielded only one result. Apparently someone asked the same question on boardgamegeek and received the following answer:


  "Yes, the vehicle doesn't need to be in the engagement for the Speeder Bay's ability to take effect."


Meaning, that yes, my speeder should have been able to damage the TIE Attack Squadron.

See post on boardgamegeek.