Did you include anything other than variable costs? I didn't follow exactly what you were trying to do, but it looked like all variable costs.

Also, your revenue number was way too high. The post by Beckles (which was for the first quarter) showed yields of $.133 per mile, behind only AA. (Stated a different way, mile per mile only AA charges higher fares than WN.) So your example flight of 1500 miles would, at average fares, carry an average ticket price of $199.50.* I don't know the exact load factor without looking it up, but a shortcut, again using the figures posted by Beckles, would be to apply the $.100 / ASM (from the same post) to come up with: 137 * (1500 * .10) or $20,550. Also, note that award passengers are considered Revenue Passengers. So you have some work to do yet on your calculations.

Rather than trying to arrive at operating income by putting averages to a flight, try using the aggregate numbers from the financial statements, which are available on the web site under investor relations.

For some recent period, perhaps FY 2007, I calculated that an average WN flight earned $600 on a GAAP operating income basis. (I'm going from memory so I might need to edit this if I recheck it .) That $600 could be gone, and then some, if fuel had to bought at market prices.

As far as other aspects of long-term strategy, I have no crystal ball. Their strategy for some time has seemed to be to deploy their superior yield management team (along with their lower operating costs and stronger balance sheet) as lethal weapons against the competition, resulting in massive losses for the other guys. Eventually gaining near-monopolistic pricing power may not actually be a formal goal, but things seem to tend to move in that direction. The only obvious major change in strategy, to my untrained eye, is the move to alliances.

* In reality the average fare on a trip of that distance would be much less, because short-haul tickets cost much more per mile. WN heavily promotes $29 fares on short routes. Those might sound cheap but even at $29 for a 150 mile flight you are paying $.193/mile, 45% more than the average ticket price per mile. That $29 fare can be $122 on a walk-up basis, or $.813/mile for 150 miles.

(Appletom's posts above came while I was finishing writing and revising; I've not modified what I wrote to reflect his comments.)