A fixed wing UAV is really a radio control airplane. There are thousands of models available, from palm sized to nearly full scale. Power can come from a battery or even a small scale jet turbine. The best format for a drone would be an inexpensive expanded foam model. These foams can withstand full speed impacts with the ground with really no damage other than a broken propeller (trust me I know). Skillfully built and operated, the fixed wing drone could stay aloft for hours and several thousand feet up. Operation is nearly silent when at altitude.