These travel cars mats are something I made for a long haul flight a few years back. They were great on the plane; the little cars tucked securely inside when they were folded up, and they fitted easily on a little table or into a handbag. They were also great for other waiting times; at the doctors, at friends' houses etc.
To make them I used some old curtains that had the white lining on the back. I hemmed them with bias binding, although the material doesn't fray, so hemming was just for looks. The bridges I made using fabric scraps sewed over some thin plastic (cut from whatever packaging rubbish we had in house). They're not super sturdy, but they do the job of getting the imaginations rumbling.
I have a snap machine to put snaps on (which I bought way back when I was first pregnant and thought I'd be using in all my endless "free time" as a new mum making cloth nappies. Ha ha!). So I used snaps for the bridges, where I'm sure velcro would probably do the job. I put a couple of different configurations in, so that the bridges can be moved around.
The road I drew on with a permanent marker, and coloured in using water colour paints. I have seen some mums making beautifully sewn on roads. I like the quick and dirty option when available.