It would be virtually impossible to accurately number UFO sightings. We are now learning that we have probably been visited and/or watched throughout human history, but until our recent technological advances we had no way to record them or even tell a 'visitor' from any number of stars or other natural occurances There were several at the end of the 19th century but even those lacked the documentation that is needed to make them truly scientifically important. So before that time we have only a very few pictures and paintings, and the occational ancient coin to prove that our ancestors saw anything 'un-earthly' in the sky.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.