According to a new study by the Centers for Disease Control, the average weight of Americans increased 10 pounds in the 1990s. Heavier fliers, says the report, require planes to burn more fuel, which in turn drives up fares. I find it hard to believe that the theoretical extra ton or two from chubby butts would seriously change fuel consumption. Am I wrong?

More weight means more fuel; there's no way around it. Two hundred passengers on a given flight, at an extra 10 pounds each, means 2,000 added pounds. Specifically, the CDC states that in the year 2000, U.S. airlines had to burn 350 million extra gallons of fuel, at a cost of more than a quarter of a billion dollars, to haul the added weight of ever-widening Americans. That extra fuel released an estimated 3.8 million tons of climate-changing carbon dioxide into the atmosphere.

Those are, if I may, pretty fat numbers, but they deserve some perspective. In the case of a fully loaded 747, which has a maximum takeoff weight close to 900,000 pounds, the sum heft of an overbooked cabin (about 400 well-fed souls) represents less than 10 percent of the total, which mostly consists of fuel (about 400,000 pounds), freight and the vessel itself.

That ratio isn't so impressive with every model, as the 747 has outrageous economies of scale. Generally, the smaller the aircraft, the more your girth matters. With the 747, our extra 10 pounds equate to .46 percent of the maximum. In the case of a 19-seater, it's about 1.2 percent.

That's not to downplay the significance of those 350 million extra gallons; only to point out that the weight of the passengers may not be as crucial to overall efficiency as you think. A less than optimal cruising altitude, for instance, can burn a lot more fuel than the expanded waistlines of those on board.

But for good measure, at least in this country, the airlines have turned proactive by refusing to feed you.

As for "driving up fares," while the impetus is there in concept, fares remain cheaper than ever. Mean ticket prices in today's dollars are the cheapest they've been since 1987. Adjusted for inflation, they are the lowest ever.

Please tell me the following photograph, sent to me by a friend who swears he took the picture himself, is doctored.

I'm willing to bet the picture is not doctored. What you see is the perfectly safe and legal application of some heavy-duty aluminum bonding tape, called "speed tape" in the mechanic's lexicon. Depending on what a plane's maintenance manual stipulates -- according to the dictates of the FAA -- certain noncritical components can be temporarily patched with this material, embarrassing as it sometimes looks. It's extremely strong, durable, and able to expand and contract through an extreme range of temperatures.

Here you see speed tape covering a crack or some other superficial defect in a flap track fairing. That bullet-shaped fairing is just a cover, a streamlining shell, that conceals the tracks and hinges of the wing's trailing edge flaps.

I have a colleague who says that when taking off from Long Beach Airport, the plane crosses over a section of the city which, because of anti-noise rules, requires the pilot to shut off the engines, and then restart them. She said the pilot gets on the loudspeaker before flight to notify the passengers.

And I have a colleague who insists that the planet Earth is only 5,000 years old, that the pope is an operative of Satan, and that a shady cabal of Zionist conspirators, in league with the United Nations, controls my neighborhood bank and the New York Times. I really hate to say it, but guess which colleague has the more credible argument?

Don't take it personally, yours is one of hundreds of implausible scenarios presented by anxious or otherwise ill-informed flyers.

Noise abatement strictures are quite common when taking off over urban neighborhoods. They might dictate a steeper than normal ascent; unusually close-in turns, and/or a reduced thrust setting during climb-out. But reducing power and switching the engines off are completely different things. No commercial aircrew, ever, intentionally shuts down an engine for any reason short of a serious problem or emergency.

With regard to your second-hand story, it's possible the crew informed passengers of a noise abatement maneuver so they would not be alarmed by a power reduction soon after liftoff. Even this is strange, however, as the changes in sound and acceleration aren't normally very drastic.

Airplanes take off and land into the wind whenever they can, but noise restrictions are one of the factors that occasionally make this impossible. Some runways, indeed whole airports, are subject to nighttime curfews.

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