The two NASA Airstreams at Kennedy Space Center (Astrovan and Telescience Van) have rear air bags that get pumped up to maximum when the engine is running.
The Astrovan has a rear entry hatch that drops down for cargo
loading and there are no front suspension air bags. The pottable
water tank is also in the front passenger side luggage compartment.
If the Astrovan has been sitting unloaded for awhile with the engine running, as it does on the shuttle runway after landing, the back end
can get up a few inches higher than the front.
The Telescience Lab Airstream (former Convoy Command Vehicle) has rear air bags tied to the engine and and front manually loaded air bags. It's pottable water is in the driver side rear area behind the gas tank. When it has been sitting with the engine off, the back end is lower than the front and with the engine on, it is level.