Perhaps it would have been better to say that fuel isn't the only reason. The Airbus A320 in this example has roughly 55% better fuel efficiency than a pre oil crisis Boeing 707, although as Jimbo's big bag'o'trivia points out, that's barely better than the 1950s era prop planes like the Douglas DC-7.

Better automation has also allowed the A320 to reduce the staffing requirements, the 707 required 3 or 4 crew to operate the aircraft, but the A320 only requires 2. The DC-7 also requires 3 crew, but only seats half the passengers (doubling the flight crew costs per passenger).

Greater competition is probably a larger factor. Talking about airline profitability and competition, Warren Buffett joked that had a farsighted capitalist had been present at Kitty Hawk for the Wright Brothers' first flight, he would have done his successors a huge favor by shooting Orville down.

There are about 1.5 million years between our ancestors discovering fire and the wheel. Iron, 2500 years after that, and then another 3000 years later, the Age of Exploration, the Renaissance, and the Scientific Revolution. It has only been 109 years since Kitty Hawk, and here we are, watching Curiousity land on Mars, a planet that is an average 150 million miles from Earth, from the comfort of our living rooms.

I must have watched the original 4fps version 30 times. Just an amazing thing for humans to have accomplished in such a relatively short span of time. It just blows me away.

That's the raw power of an EA-6B Prowler, baby! One from the VAQ-136 Gauntlets taking off the USS Kitty Hawk, now decommissioned, to be exact.