A large white vapor-like airplane was right on the tail of a small private plane...when it made a sharp right turn and dissapearedI was sitting out on my back deck...beautiful clear blue sky...when I heard plane above me. It was a small private plane..I could hear the engine....directly behind it right on it's tail was a large plane...only it was vapor-like. I could see the blue of the sky right through it. I stood up to get a better look as it was about to become out sight over the roof of my house. I saw the big plane make a sharp right and zoom off into ...no where...it just dissapeared.....I swear.... I was not intoxicated...and I am not crazy...I saw it.