The Jet Age

The introduction of jet planes brought about a revolution in passenger flying. The De Havilland Comet first flew in 1949 and went into service in 1952. It was followed by the Boeing 707, which could fly at 580 miles per hour (933 kilometers per hour) at 40,000 feet (12,190 meters). When the 707 entered service in 1958, critics argued that no airline would be able to fill its 130 seats. By 1969, however, the Boeing 747 was offering seats for 350 passengers.

Turboprop airliners, such as the Vickers Viscount and Lockheed Electra, proved briefly popular. Turboprop planes have gas turbine engines that turn propellers. They were slower than jets, but they were quiet and efficient. These aircraft were soon replaced, how­ever, by new medium-size jets.

The commercial aerospace industry of the late twentieth century had to

PRESSURIZED CABINS

The air is very thin at high altitudes, and early pilots flying above 10,000 feet (3,050 meters) would have needed oxy­gen tanks to breathe. A better system, introduced during World War II, was the pressurized cabin. Pressurized cabins were first used commercially in 1940, in the Boeing 307. After the war, pressur­ized cabins became standard on aircraft carrying passengers.

Commercial aircraft fly between 30,000 and 40,000 feet (9,150 meters to 12,200 meters). Whatever the temper­ature and altitude may be outside, the compressed air inside a pressurized cabin allows people to function as they would at lower altitudes. The pressurized air gives passengers enough oxygen to breathe comfortably. The introduced air system also maintains a comfortable temperature.

The pressurized air, which comes from compressors in the aircraft engines, flows through the wings to air condi­tioning units under the floor of the cabin.

It is mixed with filtered air already in the cabin (the filters trap any microbes) and is circulated in a continuous flow that dilutes odors and regulates temperature.

The air in the cabin changes every two to three minutes. In spite of the general belief that airplane air is full of recycled germs, airline passengers breathe cleaner air than most office workers.

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anticipate public demand for the future. Did passengers want cheaper fares in bigger aircraft, like the Boeing 747 and Airbus 380? Or would they pay more for the high-speed flights offered by the supersonic Concorde? The 747 won the commercial battle easily. Boeing 747s are still being built, while Concorde was retired in 2003. Only sixteen Concorde planes were ever flown commercially.

By 2000 Boeing aircraft had come to dominate the global market in com­mercial aviation. Boeing’s main rival is the European consortium Airbus Industries, a group of aerospace compa­nies that makes the Airbus family of commercial jets.