Air Bags

Don't forget that some of weight is also moved to the front axle of Trailer

the bear II wrote:
The airbags push down on the rear axle to raise the rear of the SUV up.

I follow you but I see this a little different. The weight pushing down on the rear axle is the same with or without airbags, therefore, I think of it as the airbags pushing up on the frame to lift the rear of the truck up higher. Probably the same as what you are saying though (is the glass half full or half empty type thing).

There is no effect on the weight that was lost off the front of the truck. The front should still go up.... but it does not.

I'm wondering if most of the front end rise on the truck without weight distribution and without air bags is actually due to the rear drop when the weight is added to the hitch and not so much related to the weight lost from the front axle (dynamics of suspension, etc). After all, with a 1200 lb hitch weight, only about 200 lbs or so is removed from the front. It is almost equivalent to having a passenger in the truck or not. Maybe the suspension automatically absorbs that type loss? Just thinking out loud.

Basically, the weight distribution hitch transfers weight across the whole vehicle. Acts as a leverage point to send some of the tongue weight towards the front of the vehicle.

Not affected by airbags since the hitch is attached to the frame. The airbags push down on the rear axle to raise the rear of the SUV up.