I think the answer is the Law of Large Numbers. Think about the total number of air missions that the US military conducts on a daily basis. If only 1% of those

I think the answer is the Law of Large Numbers. Think about the total number of air missions that the US military conducts on a daily basis. If only 1% of those are anomalous in a way that's difficult to explain, that's a lot of odd occurrences every year. No matter how high tech the equipment or how skilled the operators, there will always be events that sync up in a way that defies explanation. Even if it's only 1% of 1% that fall into this category, that's still several instances every few years. I don't question the pilots or radar operators who report seeing things they believe to be extraterrestrial in origin. But with enough missions, sooner or later the radar data will synch up with human eyes in a way that seems to indicate almost anything.