event commenced as light in the sky advancing slowly and erratic east to westerly direction. when it got closer commenced changing colors and sending multicolor beams.Colors commenced as bright red then turn violet, yellow, green. The beams were mostly of a greenish color. Only one object and moved in a way no aircraft or helicopter can. Stopped above the side of(Route BR 116) busy interstate highway at about 500 feet altitude and 1/3 of a mile from our vehicle. it is interesting to note that initially object travelled parallel to our vehicle that was travelling at about 60-70 MPH for about 20 minutes. cars, trucks and buses stopped on the side of the road and object stood stationary and quite visible for over 5 minutes. When other witnesses started to take pictures and flashing lights, object which was quite close, suddenly picked up speed very quickly and soon disappeared in a SE director climbling very fast in a circular pattern and a 45 degree angle. Witness is an airline pilot (now retired) with almost 40 year experience in aviation, air traffic control and a weather forecaster. the other two witnesses were also airline personnel which were training in Brazil at the time. observer is totally sure that aircraft was not a conventional aircraft, helicopter, weather balloon, hot air baloon, or a freak meteorological phenomenon and exhibited signs of being controlled by some form of intelligence, probably observing group of witnessess on the ground as the object seem to be responding to lights on the ground and finally departing rapidly when approached. There are no hills, mountains or radio antennas in the area of the sighting. when hovering there was a slight humming sound and the sensation of static electricity in the air even though the night was perfectly clear, with moon setting earlier in the evening and no clouds in the sky. Object was fairly well illuminated and shape was quite visible to observers. We will provide additional geographic details and sketch of the object sighted.