Agreed, small pancake or mini air compressor will do. And will be useful if you need to run an air nailer or a blow gun.
But since you mentioned trailer tires & if you travel a lot, other options are electric & cordless air compressors. Most of the major cordless tool companies have em if you are running any of the battery platforms.
Dewalt has one that can be ran on battery, 12V, or 120V. The digital ones are cool cause you can set the desired air pressure, turn on, & they will turn off automatically when they hit the set pressure so no need to sit there & watch it. They're kind of limited though in runtime & duty cycle. Project Farm has a
video comparison on some of them.
I have a 60 gal air compressor at home so I went with electric for out on the road/offroading. I wanted something better than the M12 inflator (since I'm on the MW platform) that could handle more than just 1 or 2 tires per charge & pump quicker. I went with a 12V Viair. The 400P-A that I got wasn't cheap but performs way better than the battery powered ones. If going the electric route, I'd stay away from the cheaper ones that plug into a cigarrette lighter socket unless all you need to do is top off a tire or 2.