The era between the Wright Brothers in 1903 and the end of World War I (WWI) saw tremendous advancement in aviation, with 70,000 aircraft built actually creating a pilot shortage – planes were being built faster than pilots could be trained. After the War, American aviation advancements ground to a halt. Without a push from the military to explore new technology, the American people turned their backs on aviation in pursuit of normalcy. Many aircraft were without pilots due to military cut backs, and in return, a lot of unwanted aircraft sat on the market.
In contrast, Europe took advantage of the momentum at the conclusion of WWI and were eager to re-purpose their military bombers for civilian use, resulting in passenger air travel between London and Paris. The United States did not begin flying passengers until the late 1920s. Instead, the United States government, in conjunction with the Post Office, began trial airmail service after Congress appropriated $100,000 towards the experiment. By 1920, airmail had finalized routes and was able to cut 22 hours off delivery time from coast-to-coast, flying 2.5 million miles and delivering 14 million letters annually.
The government transferred airmail service over to the private sector in competitive bid form; known as the Contract Air Mail Act of 1925.
The move was a major milestone toward the formation of a private airline industry in the United States with many airlines winning the competitive bidding process and launching their brand. Airmail was the salvation of commercial aviation in the United States.
The Morrow Board, appointed by President Calvin Coolidge, recommended civil standards for aviation be separate from the military. The recommendation was accepted by Congress and became The Air Commerce Act of 1926 which authorized the Secretary of Commerce to license pilots and aircraft, develop air navigation systems, designate routes and investigate accidents. The regulations were known as Civil Air Regulations (CARs), now known as Federal Aviation Regulations (FARs).
U.S. aviation took a positive turn in 1927 when Charles Lindbergh learned of one remaining long-range prize to obtain – the Orteig Prize; $25,000 to the pilot who could successfully fly over the Atlantic from New York to Paris, nonstop.
The Orteig Prize became Lindbergh’s quest and passion. He convinced nine businessmen from St. Louis to invest in the building of the plane; then chose Donald A. Hall, a talented aeronautical engineer and aircraft designer, to assist him in the design of the plane. Hall was working for Ryan Airlines at the time he received the request from Robertson Aircraft Corp. and immediately responded with a positive response. The two men and Ryan Airlines had sixty days to build the plane they named the Spirit of St. Louis.
James Doolittle, a U.S. Army lieutenant and aviation pioneer, became the first pilot to fly completely dependent upon instruments in 1929, setting up the future of commercial aviation. The first blind takeoff took place at Mitchel Field in Garden City, NY aboard a Consolidated NY-2 biplane. Doolittle always had a belief a pilot could fly with instruments only if given the proper tools and training. He studied the limitations of the human senses; in particular, the motion sense input (up, down, left, right) and how it correlates to the human psyche. His first instrument-only flight was a mere 15 miles utilizing a new technology package; an accurate barometer, a Sperry artificial horizon and gyroscope and a radio direction beacon for landing. Doolittle’s program and blind flight set the precedent in 1929; innovation became front and center, making the 1930s one of the most innovative decades in the history of aviation.
To make aircraft faster and reduce weight, manufacturers began using air cooled engines, rather than water cooled engines; instruments were enhanced with better compasses, airspeed indicators, altimeters, rate of climb indicators and a tool called artificial horizon which aided pilots when flying in reduced visibility – letting them know the aircraft attitude in relation to the earth’s horizon. It became the primary instrument used for weather related conditions like fog, clouds, any type of precipitation as well as flying at night.
The first air traffic controller was hired in 1929 in St. Louis, MO – Archie W. League, an experienced barnstormer pilot and mechanic. A wheelbarrow served as his control tower and with him was a notepad and a pair of signal flags he used to direct aircraft; GO or HOLD. League went on to help develop the federal air traffic control system after earning an aeronautical engineering degree. Eventually, League’s signal flags became light guns able to communicate with colors and flashes.
Radio navigation systems between the air and ground improved once technical issues were resolved. Crossed loop antennas utilized from 1928 to 1932 performed poorly by the standards set by the United States Commerce Department, especially at night. Atmospheric interference created signals that included electromagnetic interference and distortions which reduced their accuracy of measurement. The solution was the Adcock antenna array or low frequency radio range (LFR), invented and patented by Frank Adcock in 1919. Adcock, an Army officer in the British Expeditionary Force in wartime France, initially used the antenna as a receiving antenna, also known as radio direction finding. The Adcock allowed flying at night and in poor weather conditions due to the network of electronic airways. All Adcock (LFR) stations were slowly phased out and replaced with VHF band VOR navigation systems in the early 1950s, and completely decommissioned in the 1980s. Today air traffic control utilizes the superior Global Positioning System, or GPS.
Advancement in technology in the 1930s was largely due to government incentives. Bonuses were awarded to any airline that had aircraft that could fly at night, or had safety-sensitive equipment like multiple engines or two-way radios. The first airliner to meet this standard was Boeing in 1933 with the introduction of the Boeing 247. The 247 represented the first modern aircraft, one that could carry ten passengers and travel at 155 miles per hour, crossing the country in 20 hours. The 247 came with upholstered seats and an insulated cabin to reduce engine noise, and also featured retractable landing gear reducing drag during flight. United Airlines wasted no time and ordered 60 aircraft.
Not to be outdone, Douglas Aircraft Company unveiled the DC-1 in 1933. The DC-1 surpassed the Boeing 247 with regards to comfort and structure with a more powerful engine, seating for 12 passengers, and an airframe built so the skin of the aircraft bore most of the stress of the plane during flight. Passengers enjoyed more comfort and space without metal spars and it was easier for pilots to fly. It was the first plane to come equipped with auto pilot and efficient wing flaps which added more lift on takeoff. While the DC-1 was impressive for its time, Douglas only built one and immediately moved on to building the DC- 2, which was 18 inches longer to accommodate two more passengers.
Douglas Aircraft Company’s next big accomplishment was the DC-3, known as the plane that changed the world. It was the first aircraft to turn a profit carrying passengers, and only cost about ten percent more to operate. The DC-3 accommodated 21 passengers versus 14 in the DC-2, 1,000 horsepower engine versus the 710 horsepower engine in the DC-2, and could make a coast to coast trip in 16 hours – four hours less than the Boeing 247. The seating was set in rubber to minimize vibrations in flight and it featured noise-deadening plastic insulation, setting the bar high for air travel and attracting new passengers.
One of the challenges all airlines faced was altitude-related passenger sickness (due to lack of oxygen) during flights that exceeded the 10,000 feet cap. In 1938, Boeing was the first to pressurize cabins in the Boeing 307 Stratoliner. The Stratoliner was equipped with an air compressor to pump air into the aircraft as the altitude increased; allowing it to reach 20,000 feet and speeds of 200 miles per hour. The ability to fly above the weather conditions proved to be more efficient while also providing a more relaxed and comfortable flight for its 33 passengers.
Passenger assistance has existed since the 1920s, with flight attendants once called couriers and initially were sons of businessmen who had financed the airlines. After the stock market crash in the mid 1920s, couriers were let go to reduce operation costs, leaving the needs of passengers with the co-pilot. As the 1930s rolled in, the economy shifted and the need to improve passenger travel resurfaced. Assistance was initially needed to assist passengers when they fell ill from altitude, but after the pressurized cabin became a mainstay, couriers were re-introduced as stewards and assistance evolved into baggage handling, serving refreshments and assisting passengers with putting out their cigars and cigarettes. Western Air was the first to hire stewards to assist passengers, raising the bar to attract new passengers. Ellen Church became the first stewardess on May 15, 1930, flying United Airlines from Oakland/San Francisco to Chicago. The title stewardess gave way to the gender-neutral title flight attendant in the late 1970s.
Aviation advancements during World War II revolved mainly around bombers and fighters, but most of the breakthroughs were later utilized in commercial aircraft, making planes faster and able to go higher and travel longer distances. One major advancement during this time was the introduction of radar. The British used it with great success along their coast line. Scientists in Britain had been developing this device since 1935, so that could provide tracking of enemy aircraft. By the time World War II began, Britain already had radar transceivers along the coast able detect a German aircraft the moment it took off.
The development of radar continued in the United States after World War II, largely due to the Cold War. The United States needed large warning systems because the Soviet Union had the capability to carry nuclear weapons. By 1946, radar equipped control towers were unveiled, marking the beginning
of Air Traffic Control to monitor commercial flights.
The jet engine was first theorized by Isaac Newton in the 18th century when he stated a rearward-channeled explosion could propel a machine forward at a fast rate of speed. It was not until 1930 that the first jet engine was designed by a British pilot, Frank Whittle. During World War II, Whittle worked on improving his design of the jet engine and in 1942, sent a prototype to General Electric in the United States. Whittle’s design came to life in the United States-built Bell P-59. Unfortunately, the U.S. Armed Forces was not impressed with its performance and it never entered combat.
The P-59 did lead to future design ideas for United States turbojet aircraft and was the first to have the turbojet engine and air inlet nacelles integrated within the main fuselage.
The year 1947 was for record breaking. Chuck Yeager broke the sound barrier and became the fastest man alive, piloting the Bell X-1 at Mach 1.07 (just over 820 miles per hour) at an altitude of 45,000 feet. Bell Aircraft modeled the bullet shaped aircraft after a .50 caliber machine gun bullet because it was known to be stable and exceed the speed of sound. The X-1 was equipped with four rocket engines and was built to absorb 18 times the force of gravity. It was attached to the belly of a B-29 Superfortress and carried up to 21,000 feet before being dropped with Yeager at the controls and only a few minutes worth of fuel.
The experimental rocket plane was the path to modern military aviation and space flight. Yeager was later appointed director of the Space School, NASA’s precursor, where he trained astronauts to prepare for launch.
The world’s first commercial jetliner was the de Havilland DH 106 Comet, introduced in 1952, developed and manufactured by de Havilland in the United Kingdom. The Comet 1 was quite advanced for its time, with an aerodynamically clean design and quiet passenger cabin, but it came with its drawbacks and problems the moment it took off. A year after its entrance into commercial service, three Comet’s were involved in well-publicized accidents; two were the result of airframe metal fatigue and one from over-stress of the airframe during severe weather.
The Comet 1 was retired and research began into the cause of the accidents. It was discovered the plane’s square windows were partially to blame, so they were replaced with oval windows.
Other airliners took notice and used the flaws of the Comet 1 to better build their own aircraft. Despite the Comet 1’s failure and
financial loss, de Havilland went on to build the Comet 2 and a prototype Comet 3, then combined the best of their features in the redesigned Comet 4, which had a long and productive 30-year career until its retirement in 1997. The Jet Age arrived during the Cold War, when Boeing introduced a swept-back wing design in their B-47 and B-52 bombers, reducing drag and increasing speed. This same design was utilized in commercial jets, offering passengers faster flights.
The momentum towards bigger and faster aircraft continued with Boeing’s KC-135 tanker, used to refuel bombers in flight. In 1958, the KC-135 was revamped and converted into the first Unites States passenger jet, the Boeing 707; traveling at speeds of 550 miles per hour and a 181 passenger capacity.
With 17,000 pounds of thrust from each of the four engines, the 707 put commercial jets on the map with airlines lining up to purchase their own. The engines proved to be more reliable than piston engines, producing less vibration, meaning lower maintenance due to less stress to the airframe. It also burned kerosene which was half the cost of high-octane gasoline.
The 707 finally checked all the boxes for commercial aviation with Pan American being the first to purchase and fly the jet.
Commercial aviation’s pioneer, Douglas Aircraft Company, introduced the Douglas DC-8 in 1958. Although Douglas was apprehensive about producing jet airliners, believing the industry was not ready and the progression to jets would be slow, they pushed ahead with the DC-8.
The 1950s and 1960s became known as the ‘Golden Age of Flying’ and the ‘Jet Age,’ with numerous amenities offered in flight. From flight attendants catering to every passenger need to roomier cabins and complimentary services, flying was considered a luxury that most would never get to experience. Aisles were wider, seats reclined back further, and passengers were treated to endless free drinks, filet mignon and buffet tables. Men wore three piece suits and women wore dresses with heels; it was truly an era of in-flight luxury.