First P51 Campaign Mission Bugged?

[InfiniteStates]

Update for anyone who has had a similar issue on this mission...

It did appear it was bugged somehow. I did it again last night, and after killing just 2 fighters, the cargo planes dropped their cargo and the objective then changed to inspect each cargo drop and destroy a German unit by each one.

This simply was not happening before - the mission just got stuck on the "defend the cargo planes" and never moved on. If this happens to you, I suggest rebooting the game from scratch and trying it again...