I don't use a paint booth for airbrushing. However living in Arizona I can airbrush outdoors about 70% of the year. I use an old milk crate with a few wood 2x's to put my models on. While this isn't possible everywhere I like the fact that it is safer than spraying indoors, I have 360 degree access to my model while airbrushing it, and clean up is fairly easy afterwards in the area I use.
There are downsides of course. During our very hot summers, I can't spray paint very effectively. Wind can be an issue with all the dust and pollen in this arid climate. However, for the projects I have done over the years, these are minor to me.
