>>> Why do you need an airpump?
There are quite valid reasons for using airpumps. I use air operated sponge filters in fry tanks for example, a powerhead creates more current then I want. I would agree however, that a lot of people regard an airpump as an essential piece of kit when this is not normally the case. I've not used an aorpump with a display tank for years.
I have some Rena and Whisper pumps, none of them strike me as noisy, but then I don't have them in rooms that I routinely sit or sleep in.
The quietest pumps I ever had were made my "Marvel", they were piston pumps with a flywheel. Not seen one for sale for 30+ years, the vibrating pumps are so much cheaper to make. Such is progress?