“Fitness” is a word wellknown in the countries of the English language, especially in U.S.A. In Europe we used and use more for the same conception, words like “die Kondition, die Eignung, die Tauglichkeit, die Form” (Germany) or “la condition, la performance, le rendement” (France) or “la forma” (Italy, Spain). Problems of the performance or fitness belong to the sport science as long as we have the modern Olympic Games. Here will be used the word “fitness”. What are we imagining if we are talking about fitness? The definition of “fitness” is very different, there are many. For example: “Fitness is a state which characterizes the degree to which the organism is able to function” (LARSON). Which are the components of the fitness? Fitness has many spectrums. It means aptitude for a certain task, for a job, for a game, for a profession? What does physical fitness mean? How can we measure fitness? Which are the factors that impair, which are the factors which improve fitness? These are the questions discussed in which are included as well the basic idea of the special point of view in relation to flying personnel.