I have spent some time on trips looking for a place where I can get the trailer next to an air hose at various service stations. So, I decided to get a compresser I could carry along.
I bought a small compressor at Pep Boys. They carry several different units, so I just picked one rated at sufficient pressure to put 65 psi in my tires. It works fine.
The only shortcoming I have discovered is that when I clip the leads to my batteries, (on the tongue), the power wires and the hose together are just long enough to reach the tires. Just. But...it works, so that is what I care about most.
It came with a carry bag, so on the rare occassions that I use it I just put it back in the bag when I'm done and put it into the rear compartment and forget about it.
Tom