If noise limit enforcement has become a real rule in the game mechanics, Concorde will be banned from airports it actually operated at throughout its service life in real life.
The game says Concorde is "No Noise Certification / Chapter 1" which would cause it to be banned as soon as the airport requires Chapter 2.
However, in real life, Concorde was usually (after some controversial legislative discussions) exempted
from noise limits in the countries that it flew to/from. Although some countries it flew over still imposed restrictions (because they only got sonic booms and not the benefit of supersonic travel), Concorde was not actually banned from flying into or out of an airport it served due to noise limits.
For example, the US law on noise limits specifically exempts Concorde, as long as "noise levels of the airplane are reduced to the lowest levels that are economically reasonable, technologically practicable, and appropriate for the Concorde type design."http://www.law.cornell.edu/cfr/text/14/36.301
In the UK, although a noise limit did not officially exempt Concorde, the Concorde simply breached the limits and the UK authorities looked the other way.http://www.walesonline.co.uk/news/wales-news/concorde-breached-noise-limits-months-2426687
It appears that the noise level of the Concorde departures from LHR was later reduced to within the limits, but only through handling by experienced flight crew, and not with any hushkit or formal certification process. And Concorde continued to fly from LHR for the next 27 years until it was no longer economically viable and Airbus refused to do the MX anymore. (In other words, noise limits did not stop the service).
So, can this be reflected in the game, either by exempting Concorde from noise restrictions? Or, if it's easier to program, by giving Concorde a higher "effective" noise certification level (which achieves the same result), even though in real life the result was achieved by exempting Concorde from noise limits rather than giving Concorde an official noise certification?