>>> "Unidentified flying object" means an aircraft, usually a military one (because civilian aircraft are easier to identify).
There are only so many military aircraft and drones. They are relatively distinct. Add to those a handful of properly-black projects and there are perhaps a hundred types in service. Compare that to the thousands of civilian models out there, many of them very odd looking. Things like Rutan's VariEze get rather close to the flying-triangles. And some very unique objects, including random light patterns, also fly in the civilian world. So given the far greater number of civilian aircraft, outside of restricted airspace I'd say that most sightings are probably of strange but non-military flying vehicles.
There are only so many military aircraft and drones. They are relatively distinct. Add to those a handful of properly-black projects and there are perhaps a hundred types in service. Compare that to the thousands of civilian models out there, many of them very odd looking. Things like Rutan's VariEze get rather close to the flying-triangles. And some very unique objects, including random light patterns, also fly in the civilian world. So given the far greater number of civilian aircraft, outside of restricted airspace I'd say that most sightings are probably of strange but non-military flying vehicles.
https://en.wikipedia.org/wiki/Rutan_VariEze
http://www.hugeskyadvertising.com/Scrolling-LED-Flying-SIGN....