Oof, bit of a trick question: You need both! Lift allows planes to fly, but it's not only air acting from the bottom: It's generated on the top of the wing. That's why engines, missiles, and other appendages are usually on the bottom.
Think of lift this way: Pretend your hand is a wing, and you stick it outside a moving car. As air that was unmoving is now pushed down and behind your hand, the void is filled with air from above your hand, where pressure is now lower. Lift is the difference of pressure between the two sides of your hand.
The De Havilland Comet was introduced as the first jetliner in 1952, but after a series of accidents and extensive testing, the problem was identified: the corners of the square windows experienced metal fatigue, which weakened the plane's walls enough that high cabin air pressure would burst through the smallest fracture during flight. Engineers remedied the issue with oval windows, but by then Boeing released the 707, one of the most successful jet planes.
Cabin pressure is more important than you think: Planes fly so high, the air is so thin up there that humans would not be able to function. Cabins are pressurized to an altitude of around 7,000 feet. For comparison, the base level of many ski resorts is about 9,000 feet.
A "cold cat" isn't something you want to feed warm food to and wrap up in a blanket: It's when a plane taking off at sea doesn't go fast enough to attain flying speed to take off on a short runway. When that happens, a pilot go-go-gadgets and ejects before the plane hits the ocean.
Since runways on aircraft carriers are short, planes at sea are given a jump start with steam-powered catapults to help produce the speed needed for takeoff. Other fleets use something like a ski jump at the end, and when the plane faces the wind as it speeds it, the sloped runway can generate enough lift!
When air circulation systems are temporarily shut off at the gate, you have a higher than normal likelihood of getting sick.
Bacteria or virus-carrying particles hang out mostly within a radius of two seats around Sicky McGross. Tray tables and seat back pockets are portals for transferring germs, so give your hands a good scrub after deplaning.
That disinfecting concentrate and water is known as blue juice!
We've come a long with with flight flushing: Once upon a time, planes dumped their dumps out windows midflight. Then there were issues when blue water leaked and froze on the outside of planes, resulting in poop slushie bombs that would damage property when they warmed up enough to detach. Nowadays we have vacuum systems that move it to a waste port in the plane that is disposed of once it lands.
Codes that begin with "N" are reserved for the Navy! That leaves Norfolk International Airport as ORF and Newark as EWR. Other letters include "W" and "K," which are used for radio stations. "Q" is used for international communications, and "Y" is used for Canadian cities.
Airport codes are usually made up of consonants within a city's name, but what about LAX for Los Angeles, or TYS for Knoxville, Tenn.?
Some took the two-letter abbreviations the National Weather Service uses and just added an "x" (hence LAX). Knoxville uses TYS because the Tyson family donated land for the airport. And sometimes airport codes are reminiscent of a city's old name, like PEK for Beijing or BOM for Mumbai.
A lot of things can instigate turbulence, but tides aren't (at least directly!) one of them. When air hits a mountain's sides, it moves upward and can affect planes even as high as 30,000 feet and felt up to 100 miles downwind of the mountain range. A nice, sunny day can be deceptive: Bubbles of warm air, or thermals, rise and exert an upward force on anything in their path. Wind shears, or big changes in wind speed or direction over a short distance, can happen at nearly any altitude. (Microbursts are the more dangerous ones: They result from rain or storms.) And at higher altitudes, fast air currents in the jet stream can shift the air around the plane, making the plane move in the air column.
Imagine a plane as a boulder and wind as a water stream. When a plane moves through wind currents, it's an obstacle to them, just like the boulder is to water. The solution is pretty simple: Get the plane out of the "stream" and into smoother air.
Turbulence can be scary, but it rarely damages the plane or injures passengers. In fact, of the 80 cases of injury during turbulence reported in the U.S. 1981 and 1997, the majority were because passengers weren't using seat belts.
Lightning is actually less dangerous than ice! Snow is harmless to planes in the air, but the buildup of ice on an airplane's wings can disrupt their ability to create lift. Ice can also form during the flight, but many planes have heating devices to protect the windshields, wings, and other important parts.
If lightning strikes, it'll attach itself to the nose or wingtip. Most of the time, the current passes through the plane's aluminum exterior and exits through the tail.
Planes also have special strips and shielding and devices to suppress a surge, like the ones found on tall buildings. Even the fuel tank is designed to prevent sparks from reaching it.*
*Editor's note: Some of this information in the book was confirmed to be from a 2001 Scientific American article (posted 2006) entitled "What Happens When Lightning Strikes an Airplane?" Penguin Press has stated in an email that the error will be corrected in future printings of the book.