Design and usability for extreme environments: interfaces for sports aircraft - As lecturer of Communication Strategies at ISIA of Florence, a MUR Higher Institute specifically dedicated to Product and Communication Design, I introduce my case history not as a man of marketing, but as a designer and planner. In Design and usability for extreme environments, the usability is understood not as a project requirement which aims to offer improved product achievement, but as a competitive advantage capable of increasing a market, a planning approach in which the simplification of use becomes an innovative factor for the marketing of products or services. The extreme environment treated here is sports planes. Following years of the sport of flying being viewed as elitist, the advent of the ultralights in the 1980s provided a response, coming from the base, to the need to fly that had been kept under wraps. And in just a few years, thanks to the revival of a market, research and innovation have appointed new generations of aircraft, multiplying by ten, twenty times the number of users and increasingly refined means, both for technology and materials and for the performance and reliability. Through the re-evaluation of the instruments and interfaces, the behavioural model of the sports pilot and the role of light aircraft, the aim of our work is to create a new market through an extreme concept of usability, moving to increase a diverse concept of personal mobility that can lead to interesting and innovative developments, with returns to research and production. Keywords: Design, Usabilità, Volo sportivo, Interfacce, Mobilità.