Ha! Did you see Up in the Air ?
Not yet. I started watching it on a flight, ironically enough, and ended up falling asleep in the first ten minutes. Hey, I was tired and it was a red-eye. I have a feeling that it's going to be in my Christmas stocking this year.
How does the upgrades thing work if you're a frequent enough flyer?
To put it very basically, if you're a good enough customer of the airline, then you can be upgraded without charge into first class on a space-available basis, even if you've only purchased an economy class ticket. In practice, it becomes much more complex and one needs to take into account fare classes, how many other elites could be on the flight and if they have a higher status, time of check-in, and a host of other factors. In order to qualify as an elite, most airlines require one to earn a minimum of 25,000 elite qualification miles (usually by flying; miles earned with a credit card don't count for the most part).
For me, the greatest benefit isn't the first class seat, though the free liquor and food (on long-enough flights) is a bonus. It's the opportunity to check 2 bags without charge, board first to secure overhead space, the ability to do same-day flight changes without charge, and the way I'm treated when things go tits up during weather and mechanical delays. I'm often rebooked on another flight even before I know there's been any delay. Oh, and I can use the elite security lines at the airport. That alone has saved me from going crazy. The last time I flew out of Chicago, it was a Friday afternoon. The regular line was wrapped all the way around the concourse and it would have taken an hour to get through, but I was the fifth person in the elite line. Ten minutes from start to finish and I was through security. That is a lifesaver.