This dissertation focuses the attention toward inventors and key actors involved in product development projects. The study focuses on how a new product development process is carried out operationally and strategically in small, technology-driven firms. The study is based on findings from four case studies among small aircraft manufacturers, two from Sweden, one from Germany, and one from northern Finland. By using one of the Swedish cases as a platform, issues concerning the development process emerged and were summarized in sixteen statemens. The statements were then used as themes and checkpoints when gathering information from the three additional cases. The analysis has been made in two steps; first, a comparison between the platform case and the additional case were made based on the statements, second, issues emerging from all four cases are discussed. The dissertation introduces perpetual product development as a terminology suitable for explaining the behaviour found in the studied firms. A foundation for perpetual product development is presented based on both actor and process characteristics. The actors are technology devotees with numerous ideas to pursue. Their technological interest result in a preference for the first part of the development process since they experience a higher degree of technological freedom from start. Once the product starts to materialize, the actors' possibility of incorporating new technical gadgets diminishes. As a consequence, a weaker interest for the exploitation/launch phase is present. The actors also have a time conception that differs from what is normally assumed. They do not consider speeding-to-market important, since the actors prefer a superior product than being first out on the market. Their attitude toward speeding-to- market also demand actors with a high degree of stamina, since it often involves projects carried out over a long period of time. Due to the individual characteristics described above, the process is technology-driven. The process also experience a fuzzy start and culmination. The actors will continue to make adjustments to the construction even after the product has been launched, if they believe it can be technically improved. A consequence regarding the way the actors are managing their firm is that there is a tendency to regard the product development as a leisure-time activity. In view of the findings, it can be established that each case has to be evaluated on its own merits, with regard to the central actors' personal objectives. / digitalisering@umu