Growing up in Winnipeg, it was normal each fall to fit 'frost shields' to the car. "Frost shields' were a sheet of stiff plastic with a perimeter band of rubber, with an adhesive to stick to the car's glass windows, and sufficient additional rubber buttons to maintain an air gap everywhere. Canadian Tire stocked them in a variety of shapes and sizes. When visiting friends down south, we told them it was bullet proof glass.

It was standard practice to fit frost shields to gliders used to fly high in the southern Alberta wave at Cowley at least up to my first experiences there, and my diamond climbs, in the early 1980s. Then, Canadian Tire stopped stocking them. But, they did work.