The airport demand curve really depends on when during the day flights happen, and this wlll differ airport to airport. At large airports, there is likely a good volume going on throughout the day, with reduction and possibly a shut down during the night hours. So if you have one of those, as a first proxy you can probably use the standard demand curve.

Alternatively you can copy the standard demand curve and change the copy to something simple like this: origin 50% from e.g. 8:00 to 19:00, 0% from e.g. 2:00 to 6:00, gradual increase/decrease between those hours. As destination, 100% from 7:00 to 18:00, 0% from 0:00 to 3:00, gradual increase/decrease between those hours. Distance demand needs to be predominantly local, sharply reducing past the distance to the furthest points in the city and probably 0% at 50-100 km distance. See how it works and then you can tweak as needed.

i guess mostly the issue was that the standard demand curve seemed to simply not do anything when i set up a POI with it and some population, might've been a bug though cause that was early in 1.12, might try again in a bit

(sorry messed up the version)

look at the busy-ness graph in google maps for your local airports.

Also the type of airport matters. A business city like Frankfurt, New York or Tokyo will have other patterns than tourist destinations like Mallorca, Cancún or Phuket - usually business takes place on weekdays while tourists tend to travel on the first days after or last days before work, i.e. the weekend. That is why, probaby not only in European air travel Saturday is nicknamed "bunk change day".

Originally posted by Rampagerslife:

i guess mostly the issue was that the standard demand curve seemed to simply not do anything when i set up a POI with it and some population, might've been a bug though cause that was early in 1.12, might try again in a bit

(sorry messed up the version)

Did you set up enough population? If you operate at 100% global demand setting (default), this is intended to translate to number of pax equal to 25% of population over 24 hours in a typical large city and typical demand curve. If you want to see 10,000 actual pax going out of the airport by train, I would set up POI at 40,000. If you operate at higher or lower global demand setting, you would want to adjust these numbers further.

Also, airport as destination competes with other destinations. So in general you would expect to see fewer people go to the airport than originate from the airport if the airport demand POIs are the same for origin and destination. This is why I set up in the example above origin demand at 50% max and destination demand at 100%. So in the above paragraph, if you get 10,000 pax spawned in airport, you may only see 5,000 go to the airport. To address this, further increase POI e.g. to 80,000 and reduce the origin demand to 50% or less.