In the first picture you can see the noise pollution view of my airport in my city. As you can see the airport produces 0 noise pollution. Meanwhile in real life airports are some of the noisiest places on earth. In the other picture you can see a noise pollution map of a real airport.
Colossal Order must just have forgot to add noise pollution to the airports, cause it's obviously common sense that airports produce huge amounts of noise pollution.
Transport Fever 2 does a great job of airport noise pollution, making not just the airport noisy, but also the path the planes take while they are still low to the ground. Just like the IRL picture I added.