Anyone towing any significant load (other then boats) should be using a WD hitch, which eliminates squat and headlight blinding, and air under heavy load for leveling gets extremely firm. This is the big problem with air, it’s good with mid stroke suspension compliance, but when you increase the pressure to raise up or level under load you lose travel, articulation, and ride compliance.
Also air is not the only option for adjustable ride height, hydraulic with springs like Toyota Land Cruiser, Oshkosh, and even GM magnetic is superior to air for consistency when increase height and under load. These systems actually give decreased spring rate (increased travel/articulation) when raised and maintain suspension compliance under load.