Warm boots for cold flying days

My college roomate was from Vermont (similarly liberal users of road salt). We're driving in his early 1980s Subie when someone pulls out in front of us. He hits the brakes and I instinctively plant both feet firmly on the floor. As we stop, I look down and realize I've just pushed right through the floorboards, and I'm staring at pavement.

Of course, being in college, we just found a piece of plywood, cut to fit, and went on with our lives...