We've got two Viair brand compressors behind the back seat of our Ford pickup and a 5 and 7 gallon air tank hooked in series and attached to the frame. A quick-connect air fitting in the rear bumper for the air hose.
Make sure to add an air dryer if you want to use it in the winter else the airlines will freeze. And make sure you buy the highest volume compressor they make.
We love it and so do our friends
. It takes about 2 minutes to build 150 psi and we can pump up two big kites in a minute or so with the 12 gallon reservoir.
It also fills our suspension airbags and has bailed us and others out of trouble with flat tires.
I think I've got about $400 in the whole system including a couple tweaks and repairs over the last 5 years or so.
Oh yeah, If your driving around in the winter on salty roads put the pressure regulator inside somewhere instead of on the airtank or they'll rust apart in a couple years.