Interesting thread... and yes, airbrushing can be a messy business, as Stuart says, especially in larger scales! I used to open the garage door and spray hopefully into the open air... if the wind was blowing the wrong way... well, what a mess... I got really lucky when my good friend Albert emigrated to Australia (a frequent past time here on the Southern tip of Africa) and left me his hand-made spray booth, that he put together with Doug, my other really good friend, who helped me install it in my model-filled garage... No cost to me, and I don't know exactly how much it all cost to put tother, much less than 50 US dollars, I'm sure... Based on a wooden box with a double floor, a bathroom extractor fan and three (!!) internal lights with extractor pipe... it even has a door that you can lock... note the switches upper left on the top for fan and lights...

Then it has a perforated aluminium floor on the inside that leads to the extractor fan, and three lights protected by glare shields...

Here is a closer view inside with a 1/32 Polikarpov I-16, so there is plenty room, the air is extracted through the multiple holes in the floor, so the dust is dragged downwards with no turbulence with the airflow, and no discernable wind to upset the spraying...

And here is a view of the back, I had to turn the box a bit to show where the extraction fan is housed in the silver foil area and the ducting going up into the roof, a really big area in the roof so no problem... It's actually all relatively quiet, just a hum from the fan... No-one has complained yet...

The first design had the fan suck from the upper right corner of the box, that "hole" is now covered in perspex and the "Floor sucker" works so much better... I have my friends to thank, I could never have done all this on my own... but just to show it's possible...
Regards,
Marc