It's a pop-up camper, note the lift cables in the post#1 image.
If the top is lifted quickly enough the momentum can lift the base box off the ground. A suitable high shutter speed on the camera allows capturing the moment of 'wheels-up' without image blur.
I thought about the possibility of it being hooked up behind a low-rider tow car but the lack of high speed hydraulics on the
axle ruled that out.
It's not necessary to be right, just persuasive.