Thoughts on City Demand and Slot Management
Where the City Demand isn't being met then additional Runways or Airports could be 'created' in the game (by the game managers or by Airlines?) or by expansion of Luton/Stanstead (to support Heathrow/Gatwick?). As a new London Area airport my personal favourite is the old USAF base north of Oxford where existing rail and Motorway links are within a couple of miles and within 70 miles to London, Birmingham etc. It could have been active in a few years with a single (existing) runway but is now becoming a housing estate. Lets change history a bit.
The proposed high speed rail link from London to Manchester will allow Pax demand to relocate to more than just the 'local' airports. It is already proposed to have passport control at both terminals and Manchester Airport EGCC currently operates at 60%, something the game doesn't really reflect.
Airport PAX numbers are a big issue in the real world too so maybe, after Cargo is sorted, the proposed City Pax model also needs to control the available Take-off v Landing slots by demand in each hour. Heathrow routinely use both aircraft for landing at times spaced alternately but doubling the landing rate for short periods at the cost of take-off slots. As a trial perhaps it could be manually changed for major airports slot limited airports only, say each game year, as traffic levels grow.
While the game is sticking to real world traffic growth levels and fuel costs that is becoming a bit predictable which doesn't model the real world's airline management issues.
It is right that the aircraft should come on-line to historic data, there's no need to change that. I applaud the way production of models in demand continues while demand is there, plus the additional nearly made it models that have been added, much kinder to UK Aircraft industry than the real world was.