I was the only passenger aboard a Pioneer Airlines SWM between Cortez and Denver. Small plane, there - maybe 30 seats. As for larger planes, I once flew an Alaska 737-900 from Anchorage to Seattle that had two up front and four in the back. The first 747 I ever flew, on Continental between Chicago and Denver, had only 3 of us back in the Economy Section - which was different from Coach back in those days. Either way, about 130 seats and a lounge for the three of us.