NASA: Stothers 2007 Stothers, R., 2007: Unidentified flying objects in classical antiquity. Classical J., 103, 79-92.

A combined historical and scientific approach is applied to ancient reports of what might today be called unidentified flying objects (UFOs). Many conventionally explicable phenomena can be weeded out, leaving a small residue of puzzling reports. These fall neatly into the same categories as modern UFO reports, suggesting that the UFO phenomenon, whatever it may be due to, has not changed much over two millennia.

 

https://pubs.giss.nasa.gov/docs/2007/2007_Stothers_st02710y.pdf