It was in 1994 when I was 14 years old about 5 o 'clock p.m. and I was on my way to Arheilgen which is a village in the vicinity of my home. I was sitting in the bus and the bus turned to the left side and drove along a corp field. I saw this brown, oval object moving slow above the corp field and than I thought it was a hawk or any other bird looking for some food but it was no bird but something that I was not able to identify. It was to big to be a bird. it also had an oval form and it didn't make any sounds. It moved slowly first, it had no lights and than it accelerated and moved very fast to the left side stopped immediately and than it flew back to where it first was. it changed its direction again to the right side and was again very fast and absolutely loudless, faster than an airplane! than it flew back to the position where I saw it for the first time.it was no helicopter and no other familiar object. it all happened within one minute and I realized that it is an UFO. Than it vanished. I haven't seen it again.I am not sure if there has been any other observers but I am very sure that it was something that I cannot classify! As I have been working for years at Frankfurt Airport and at airplanes I can defininetely say that it was NO airplane.