Judging by the current trend in oil prices, your cheap airfares are about to disappear for good. Salon's
Ask The Pilot has more.
In short: jet fuel costs more than anything else airlines pay for, and it's way past the feasible business model range. Jet fuel was 86 cents per gallon in 2003, but is around $6 today. Let's say you fly a 767 with 300 seats across the Atlantic on a 5-hour flight. That plane could burn 50,000 pounds of jet fuel, or almost 8000 gallons. At the current $6/gallon, that's $160 per passenger. One way. Then the airline has to pay for the plane, the crew, the landing fees, and food, the toilet paper, and so on and so on. (note: all specs approximate)
I'm glad I'm earning lots of points this year, because I sure won't be next year.
Note: numbers updated based on different estimates I found.
Another note: I found more numbers
here, so I think the numbers could be as high as $400 per person, one way, in the above example.