I've been an American Airlines AAdvantage® member since Wednesday, June 09, 1993, making today my 10th anniversary. Since that time, I've flown 529,909 miles. Using Fermi's "simple and intuitive way to deduce the circumference of the earth", that means I've flown enough miles to circumnavigate the globe 22 times! Using figures from AMR Corporation's
1999 Annual Report, the total cost per available seat mile is 9.39¢, which equals $49,758.36 in cost, for American. Using American's yield (the average amount one passenger pays to fly one mile) figure of 13.12¢, I've paid American $69,524.06 for all those miles, giving American a profit of ~$20,000.
Of course, "I" paid a lot more than that most of the time because the majority of that milage was accrued through consulting travel on expensive tickets. Still, ~$70,000 for 22 trips around the globe doesn't seem as insanely expensive as I thought it would be when I started all these silly calculations.
What's really incredible about all the flying I've done is that for more than a year during that time, I traveled exclusively on Continental Airlines, and probably racked up another 100,000 miles with them!