Viewed another way, I've been on about two dozen flights since 9/11, and NONE of them has been full. Revenue per empty seat: $0. Revenue from me: Typically one or two hundred dollars per segment. Incremental cost to carry me: maybe $10.

By selling discount tickets on flights projected to have empty seats, the airline can push nearly all the revenue from me to the bottom line as profit. A good deal for all of us. I don't need to fly on high-demand flights, since I'm retired and traveling for pleasure. In fact, I PREFER the more lightly-booked flights.

My airline, American, seems to understand this, and has made me feel very welcome. Not out of charity, but because it's good for business.