I have been playing a save game for many days without any issue but this evening all of a sudden flights are no longer arriving at my airport even though they are scheduled. I have tried exiting the game and coming back in which some aircraft land I then get warning about delaying the flight but before I can do anything they start taking off without any passengers and then no other plans land.
Sometimes when I load the game staff stop doing anything and at security even though staff are manning the checkpoint it says it’s unmanned. If I destroy the checkpoint the staff stay in place.
These are certainly bugs, have you reported them with the ingame bug reporting tool? That’s very usefull for the dev’s because it includes a copy of your airport, log files and specs. These are all valuable for them to sort these issues out.