This document discusses non-pneumatic or airless tires. It begins by introducing traditional tires which use air pressure inside a tube to support the vehicle's weight. It then defines non-pneumatic tires as those that do not use air pressure, instead using flexible spokes and treads that deform temporarily under weight before returning to their original shape. The document reviews several approaches to non-pneumatic tire design from NASA, Bridgestone, Michelin, and others. It notes advantages like resistance to flats and punctures but also disadvantages like lack of adjustability and potential for more vibrations compared to traditional air-filled tires. In conclusion, it suggests this new technology could increase safety and have environmental benefits.