The Adidas SLVR S-M-L Concept Shoes are not really a concept at all, you can buy them here for $140. The SLVR shoes are airport friendly in that they have a 4-way stretch mesh upper which makes them easy to slip on and off. The shoes come in small, medium, and large but can fit from men's (UK) size 4 to 12. Even the sole of the shoe has the ability to stretch. If nothing else, I am sure they would be very comfortable shoes.