This paper presents the preliminary results obtained within a research project aimed at the development of a remote sensing system for forest fires monitoring in missions of compact airborne platforms. The core of the system is an integrated, multi-/hyper-spectral suite of electro-optical sensors. They were selected to get enhanced ability in forest fire detection and monitoring. The system is completed by a dedicated on-board computer for sensor control. It is capable of autonomous operation and it is also in charge of data exchange with the on-board navigation and flight control system. Two different configurations are described, relevant to different aircrafts: a mini UAV and a certified, two-seat light aircraft. Results of the first flight experiments are presented, that highlight performance achievable by the system.