I do believe if you can find out what cal's casm (cost per available seat mile) is then you are probably in the ball park. To fly one seat one mile = 1 available seat mile, which may cost anywhere from 8 cents and higher for a carrier like Southwest. If you multiply the number of seats on board X number of miles the aircraft flies = number of seat miles. Example.... a 200 seat airplane flying 5000 miles = 1 million seat miles. Multiply the number of seat miles by the casm and I would say that is a good start. So, if the casm is 10 cents X 1 million seat miles = $100,000.