UFO camoflague

I was thinking, if i was an alien and didnt want to be seen flying id put flashing lights on my craft and send smoke out one end.

who said they dont wanna be seen

If you watch the Dan Akroyd/Sereda Video,

video.google.com...

Sereda explains how UFO's disappear. He suggests that if their engines whatever them may be run at higher frequencies, much higher frequencies that those frequencies would be unseen by the naked eye. Just as with our hearing there are limits on our vision. Sereda states that anything outside our frequency range will go as unseen unless we have a infrared camera.