Grab a globe from any classroom and put a dime on it. Lay it flat.
That’s about how thick the layer of atmosphere surrounding Earth is. Now there is some air all the way out to hundreds of miles, but 98% of our protective coating of air is beneath the top of the dime.
A gentleman in West Yorkshire has shown visually just how thin our life giving coating of air is- See the video on the BBC. Just click the image.