Why must your seat be returned to the upright position? What happens to all the stuff confiscated by security officials? Here are answers to all your burning questions about air travel.

1. Why Must Your Seat Be Returned to the Upright Position?

"Put your seat in the upright position, make sure any carry-on luggage is placed under the seat, and stow away your tray table." Why does any of this matter? Note that these instructions pertain specifically to the period during which the aircraft is either taking off or landing. Should an emergency occur during either of these times, passengers often have a good chance of survival if they evacuate the plane immediately. Milliseconds count in these situations, so passengers are naturally in a rush when finding their way to an emergency exit. Coach passengers know how difficult squeezing out of a seat mid-flight just to get to the lavatory can be; now imagine that the cabin is filled with smoke and visibility is near zero. Reclined seats, extended table trays and briefcases in the aisle will cause already panicked folks to stumble and fall and hamper the evacuation process.

2. What Happens to Items Confiscated by Security Officials Prior to Boarding?

It depends upon individual airline policy. If there is enough time left before boarding, passengers usually have the option of packing the forbidden item into their checked luggage or running outside to stash it in their car. If time has run out for that solution, passengers can request that the airline send the item to "lost and found" so they can claim it upon their return. However, there are no guarantees that they'll be reunited with their keepsake. The majority of confiscated items ultimately end up in an industrial-sized incinerator or trash compactor.

These days, the most common items accidentally left behind at airport screening terminals are personal computers. Security regulations require that they be removed from their cases for inspection, and many harried travelers simply grab the empty case as they rush to catch a plane. Denver International Airport once posted "Got Laptop?" reminder signs after they collected 95 of the devices in only 30 days.

3. Where Do Airport Codes Come From?

Some airport codes are easy enough to decipher; Boston is BOS, Miami is MIA, and Salt Lake City is SLC. But what about some of the more unusual codes? Why is Chicago ORD and New Orleans MSY? The names become less mysterious if you know some history about the airports. For example, before Chicago's airport was named after Butch O'Hare, it was called Orchard Airport. New Orleans' code is derived from the property's original purpose "“ Moisant Stock Yards.

The FAA began to issue three-letter identifying codes to airports back in the early 1930s. The oldest airports were simply designated by their official weather station code, with the letter "X" added to the end. So the Los Angeles Airport became LAX, Phoenix was PHX, and so on.

Incidentally, that tiny sand dune in Kitty Hawk where the Wright Brothers made their first flight has its own location identifier: FFA, for First Flight Airport.

4. What Are the Hottest Selling Items at Airport Shops?

Sometimes it's a regional thing. Miami International is the nation's largest airport retailer of Spanish-language books. Decorative Western saddles (which sell for upwards of $2,000 each) are very popular with international travelers who pass through Dallas/Ft. Worth International. But in 2006 one particular item was selling out at airport newsstands across the country: mechanical pencils. Closer study revealed that the pencil passion was caused by the Sudoku craze. Passengers liked to fritter away their flying time with the popular number puzzles, and most airplanes don't come equipped with pencil sharpeners.

5. Are Pilots Allowed to Chat?

A "sterile cockpit" has nothing to do with the cleanliness of the flight crew. Sterile cockpit is an FAA rule that requires pilots to refrain from non-essential conversation during critical phases of flight (usually any time below 10,000 feet). Airline pilots like to chit-chat while on the job just like anyone else. It's only natural that a task they perform thousands of times becomes automatic and a little gossip while breezing through them would make the process less mundane. However, prior to take-off, the FAA prefers that cockpit personnel have their minds 100% on the task at hand. Any extraneous conversation could conceivably distract the crew and ultimately cost lives. Take, for example, Delta Flight 1141. According to the CVR, prior to takeoff, a flight attendant stepped inside the cockpit, and the group proceeded to discuss their favorite cocktails and the dating habits of other employees while simultaneously running the pre-flight checklist. The NTSB determined that the crew was distracted and failed to properly configure the flaps and slats, which caused the plane to crash shortly after takeoff.

6. When Did Airports Beef Up Security?

Airport security was virtually non-existent until a rash of hijackings occurred in the early 1970s. In December 1972, the FAA issued an ultimatum: all U.S. airports had one month to install the necessary equipment and procedures to ensure that each and every passenger and bag would be properly screened.

The first metal detectors used at most airports were large, clumsy devices called magnetometers. These machines were originally designed for the logging industry.

(If a piece of metal is present in a log, it can severely damage the saw, so the magnetometer was devised to prevent saw mill shutdowns.) Unlike the door-frame design of today's metal detectors, the original magnetometers were tunnels about five feet long. Passengers walked up one ramp to enter the device, and down another to exit.

7. What's So Bad About Living Near an Airport? (You Know, Besides the Noise and Traffic.)

Just like prisons and meat processing plants, airports suffer from "Not In My Backyard" syndrome. However, it's not just the noise and traffic that make living near an airport undesirable; the construction of an airfield can actually change an area's weather patterns. Because expansive areas of land have to be flattened out, the surrounding tracts may suddenly become more susceptible to fog. The miles of pavement necessary for taxiways and runways can also change drainage patterns, which may lead to problems with flooding and soil erosion.