Are there any remaining problems regarding the airplanes (when grounded)?
They should now:
- fight with the very reduced values of a convoy (and being shown as such)
- automatically return to their airbase and turn into a convoy when the city is captured or the airfield destroyed
- start fighting the city garrison or other ground troops in range
Yes. They seem to not know when a city has been taken over. A Polish plane was bombarding Minsk from Warsaw, even after the British took it over. Even so, it froze the entire British army for 6 days because the entire British army was fighting it. So, I would say yeah.