A few years ago, I showed up at WKJ (Wakkanai, Japan), on a bicycle, 30 minutes before departure for the last flight to Tokyo, without a ticket. I handed over a credit card and one of the ground staff issued my ticket while another helped me pack the bike into a carry bag and check it in. Got my boarding pass, went through security and flew off without a hitch.

This sort of thing could never happen in the US, even at a small airport.

I never had to show ID or take off my shoes.