As far as I can tell whenever you can exectue a
Delegated Maintenance you should do that and the plane is ok after and generates passive income regardless if you still see some exclamation marks on the list on the right.
With so many planes you will need a tool for the maintenance or your time spend on manual maintenance and with this inhuman unusable UI will turn you crazzy.
I worte a standalone tool/program for exactly that.
Started it every day the time I was still flying career and could go flying after the day and was sure that I get passive income from all my planes. (I have 200)
Also with the tool it takes around 40min for the maintenance of the 200 planes but at least you can do something else and stay mentaly sane.
You can find it in the
Section Tools & Utilities of this Forum with the Title:
Career Maintenance Tool
It is open source and on GitHub.
I also read someone made an autokey script or something. There was a post in one of this general disscution thread in the middle of a disscution.
So if you don’t trust my standalone exe you might search for this script alternative.