I was in the Aviation industry for 30 yrs, and have spoken to pilots, who have had the scares of their lives with "unexplained airborne phenomena". A mate of mine who had 30,000 hrs commercial flying was formated by a disc shaped object from the Flinders Ranges to Port Augusta, it just kept pace with him and from what I recall it was flying just under one of his wings. When it finally disappeared in an instant, he was one relieved man. When he landed at Adelaide, he was a white as a ghost. Also had another one whilst talking to a BA Flight Sydney to Nadi, in early 70's where the Captain asked me for traffic in his vicinity, as I was only doing the communications for ATC, I conferred with them and was advised there was nothing within 100 miles. The captain advised me there was a large silver disc same level and heading and track about 1/5 mile in front of their aircraft (B747). I asked him if he wished to submit an incident report, and he replied in the negative. I also had numerous "incidents" whilst stationed in Darwin.