The powers that are: with a few exceptions in the higher-flying types that are powered by adapted aviation-extraction turbo engines, almost all drones are driven by piston engines that often find their origin in recreational ultralight aviation. But even this segment is now maturing in its new role.(Complete Guide)

The exception that confirms the mastership in the turbojet engine field notably draw nears from the two companies Microturbo (part of Snecma) and Williams whose engines are almost ubiquitous in cruise missiles and high-speed target male honey-bees

The widest variety draw nears from the traditional piston engine manufacturers (including rotary piston, if individual can now include this in the traditional category). Clearly the leaders here are UEL (or UAV Engines Limited), followed by means of Rotax (who apparently is not too earnest on being publicised as defending suppliers) with now Zanzottera, ATS and Denel emerging