cover for models while paint drys?

I don't cover mine nor keep it enclosed after painting. I simply set it down somewhere away from my painting area to dry.  It's all a matter of preference of what you want to do.

Most of my paint jobs have already flashed over by the time I sit them down so I don't cover mine either.  I don't guess it would hurt though.

For me it depends. If its something I'm going to weather I don't worry about covering it. If its something I want to have a smooth finish or a showroom shine (like a new car) I cover it.

Something to consider is certain enamel paints like reds and yellows can take days to dry. These I also cover.

Whatever container does need to have some venelation holes to allow gases evaporating from the paint to escape.

I'm pretty lazy and don't normally bother to cover. Like CN Spots said, the acrylics i use evaporate off very quickly and are normally touch dry by the time i put the model down.

If i use enamels, i place the model in an (empty) old fish tank - with glass covers. The covers are not air tight so the fumes of the paint can still escape.

I use just an inverted cardboard box, like a shoe box, over the model as it sits on the workbench.

I used to just cover them while drying.  However, since I use enamels I got tired of waiting a couple of days for it to dry, so I finally made a drying box. I used one of those plastic storage containers that we bring our models to contests in.

I built a box out of particle board, with holes in the top and in one side, for convective air flow (I covered the holes with a filter to keep dust from coming through.  The box has a socket and a 60 W light bulb for heat. I turned the plastic storage container upside down, so the cover is now the base of the upper compartment.  I cut out the area of the top that matches the area where I drilled the holes in the particle board box, then screwed the cover down.  The container itself is then set, upside down, on the cover. I cut a one inch hole in what is now the top (was the bottom), and taped a filter over that hole, which allows air to flow through the system.  Works beautifully, greatly speeds up drying and keeps dust off.  Because of the slow drying time of enamels, especially gloss enamels, some such system is a real help.