I have a kind request to the Devs. You did a really great job delivering the major milestones we’ve been chasing you - remote stands, multiple floors, landside enhancements, big birds.
If the progression is not written in stone yet, I’d like to add my 5 eurocents to the airline ratings. Currently when you pass to **, all of the flights suddenly become **. Seriously, even Cessna 208 - a single flight with 4 pax is worth 5k income.
I would encourage you to treat rating as max, the ceiling. Meaning, if your terminal has jetways, you can serve *** flights, but you will still have * and ** airlines and flights in the pipe, so you can distribute which flights go to contact stand, which go remote. Breaching these rules would enforce dissatisfaction or penalties.
I would also HOPE to be able to sign auxiliary services PER AIRLINE. So only airline ABC would get the baggage system, only airline DEF cabin cleaning etc. That would allow easier progression as currently baggage system (and the rest) needs to be deployed to all boarding desks, stands, planes and airlines at the same time.
With these features in place I (plus, cargo perhaps) I would treat the game as a complete and superb product!