Chicago has the world's 6th busiest airport, with hundreds of thousands of aviation operations every year. Naturally the people who live nearby get an earful. I live about 16 km east of the approach end of runway 28C, the preferred landing runway from destinations south and west of Chicago. Even though the planes are about 4,000 feet up when they cross the lakefront, I can still hear them well enough to tell them apart by sound. (No machine in the world sounds like a 747, I assure you.)
Starting today, the airport will use a rotating arrangement of landing and departing runways for nighttime operations (10pm to 7am). Despite its name, the "interim fly quiet" plan won't actually reduce aggregate noise emissions. It'll just spread them around more evenly:
Currently, O’Hare uses just the parallel, east-west runways at night. The so-called “Interim Fly Quiet” plan will mix in diagonal runways, so an east-west runway will be used one week, then a diagonal runway the next, then back to east-west, with adjustments made depending on weather and other factors.
It will mean more noise for suburbs like Des Plaines, to the northwest of the airport, while areas more directly east or west, such as Bensenville and some North Side Chicago neighborhoods, will get less.
Note that this only applies to nighttime operations, when planes land about every 10 minutes. During peak hours, O'Hare brings them in on two parallel runways at 90-second intervals. When runway 9C/27C opens soon, it will be possible for O'Hare to land one plane a minute on 3 parallel runways.