I don't mean any disrespect, but I don't find the bible based answers helpful. Those are faith based responses you either accept based upon your religious beliefs or you don't.
I want to know what those pilots saw- what factual data do we have of these encounters, and what the possibilities are.
Their targeting systems achieved lock on an object. That seems to be fairly solid proof something was there. Do the flight characteristics of those objects match any known terrestrial technology under development or in planning?

"For what shall it profit a man, if he shall gain the whole world, and lose his own soul?" -- Mark 8:36