I lived in Kowloon when Kai Tak Airport was still in use. We had planes flying super low above our place all the time everyday.
Here is a picture I found on Wikimedia Commons that illustrate how low were the planes.
https://commons.wikimedia.org/wiki/File:KaiTakAirport-2.jpg
It was very noisy as you can imagine.
The schools in Kowloon had air cons installed pretty early when air cons were still considered expensive and not very common among school buildings. It was necessary because the windows had to be closed for all time for soundproofing.