[K0balt]

The problem is the salvaged aviation turbines. Airplanes are prevented from operating at high power levels above cities. These engines-from-old-airplanes are likely being operated in their high efficiency range, around 80 percent, so they are loud. Living next to a runway loud.

[SoftTalker]

Airplanes can't carry much in the way of sound supression or "mufflers" on engines. Running them on the ground, it should be straightforward to make them reasonably quiet.

[K0balt]

The sheer volume of air moved by high pressure gas turbines makes that large and costly. Not impossible, but very large. These units are 2 per container size, intake and exhaust silencers would probably increase their footprint 5-8x. Not that it shouldn’t be done, just that there’s a lot of incentive not to do it.