Have I seen Unidentified Flying Objects? Yup. Alien spacecraft? Nope.
Some UFOs might be ball lightning. My Mother tells the story of when a bolt of lightning hit a tree outside her school room in Poseyville, Indiana, when she was about nine years old.
The tree split and a ball of lightning came "slowly" toward their room, burned a six inch hole through the glass, dropped to the floor, rolled down the aisle between the desks one aisle over from hers, and out the door into the hallway, all the while making a loud "frying bacon sound". Out in the hallway it hit a radiator and exploded with a bang!
The scorched pathway was still visible in the school room floor fifty years later.
Are all UFOs some form of ball lightning plasma phenonomon? Page Nicola Tesla... he might know.
Who in the Galaxy would want to come here if their technology was so advanced? Surely the universe offers better attractions.