Using 2.79, since 2.80 crashes\fails startup, I used ctrl-J to combine all the objects into one for easier animating. but when I went into top ortho view to work on the launch pad lo-and-behold my fins are 2D again
!(thank goodness for saving multiple files so I still have a good copy) Do I need to apply the modifier on the fins before using ctrl-J? Or, Can I just parent all the rocket parts to the main body of the rocket, cause wont that cause the other parts to move with the main body too when animating?
It's weird that it's doing that. I'd just apply the modifier before joining the fins together. It'll be the quickest and easiest solution to your problem.
Alternatively, you could parent them like you mentioned, but you'll have to be careful to not accidentally drag them off when you're animating the rocket!