Airports Stuck at lvl 5 Traffic Level

[tungstennedge]

I'm not sure if this is intended or not, but airports seems to be stuck at lvl 5 traffic level, and cant get higher in some of the newer worlds I'm in, speedworld, and hatf. In hatf(1973), airports like LAX and ATL, and LHR serve 50+ million pax per year, and much cargo on-top of that, yet the traffic level stays at 5, which in other worlds like modern times are achieved quite easily with as low as 10 million pax per year, and almost no cargo.

Seems like its a bug, or is there a really high requirement for traffic level 6 in the newer games? Also, I dont think its tied to date, as in Speedworld(1997) top airports are also exceeding 30+ million pax per year, and even more cargo that hatf, but the traffic level still seems locked at 5.

This restriction is hurting my cargo plans, and I'm wondering if anyone knows if this is intended behaviour or not.

[Sami]

The traffic (and also infra) levels have certain caps to make them grow in a more linear and realistic manner. Factors are game year and the time from the start of the game world. For example in 1980 maximum traffic level is 6.