Originally Posted by
YoPhilly
This is where I get confused. How/why did you use 66,000 to get the per mile cost? Why not use 55,000, which works out to 2.9 cents?
Because if you paid X dollars, you'd not only get the flight, but you'd get the 11,000 miles. So your swing is from a negative 55,000 miles to a positive 11,000 miles - a difference of 66,000.
In another way: you're not including the value of the miles earned if you just ignore the 11,000 miles from the equation. The 11,000 reduce the real cost of the $1600 flight.