An interesting calculation in regards of cost is the pasenger mile per litre. If you take the cruise speed, multiply by number of passengers and divide by fuel burn in litres you get the amount of fuel to move each pax a mile! So consider a Cherokee Six. 60ltrs/hr six up and doing 135Kn @6000' 135 x 6= 810 passenger miles. Divide by litres and you get 13.5 passenger miles per litre. This plane is the cheapest i have found for touring, but it does need to be atleast 4up to make it pay. BTW i rent one from Turweston as most of my flying is one or two up so it works out cheaper to keep my 172 and rent when enough pax are available to make it cost effective. Try doing the calc for a few types and i think you will be surprised at which planes are more cost effective for certian flight profiles. Sorry for going off topic
