I've been on some pretty empty flights, but the only time I was alone was a little 6-seater from SCE to DTW in 1996. When I was waiting in the gate area, the GA came up and said "you're the only one on the flight. Your plane is going to pull up right there and stop. As soon as it stops, run out and get on." When I got on, the pilot looked like he was maybe 15 years old and zipped through the safety announcement at a thousand words per second, giggling. He left the curtain open during the flight and I could see him sort of bouncing side to side, like he was listening to music on something. He was probably making his own airplane noises, but I couldn't hear because of the real noise of the plane.