# Qualitative Analysis
## Mode Description

Passenger aviation is most frequently used to transport travellers moderate to long distances. Pressurized cabins and jet-powered engines are common, but my no means universal. Scheduled passenger service operates out of commercial aviation terminals, as opposed to private airstrips or military airfields. Passenger aviation has been around since the 1920s, and has grown steadily as technology has advanced and as the general public has become accustomed to the speed and relative comfort of flying.

## The Scene

Prior to the advent of civil aviation, long-distance travel was time consuming. Over the course of the 19th Century, developments in transportation technology greatly decreased the travel time from coast to coast. Early Mail coaches took three weeks between Missouri and California; Railroads made the journey in 8 to 10 days. By the early 1900s, railroads could complete this trip in 5 days. In 1903, the year in which the Wright Brothers successfully sustained powered, heavier-than-air flight, Dr. Horatio Nelson Jackson completed the first transcontinental automobile trip. From San Francisco to New York City, his journey took 63 days to complete.
Over the early decades of the 1900s, the time taken to travel via air from coast to coast decreased dramatically, as seen in the chart below. The standard of 5 hours from coast to coast remains in place to this day.
| Year | Equipment | Coast-to-Coast Flight Time |
| 1930 | Ford Tri-Motor | 36 Hours |
| 1934 | DC-2 | 16 Hours |
| 1940 | Stratoliner | 14 Hours |
| 1946 | Constellation | 10 Hours |
| 1959 | Boeing 707 | 5 Hours |
Whether by car, railroad, oceanliner, or wagon, travelling between the coasts of the United States was a time-consuming, dirty, and often dangerous undertaking. Early aviation was often so, as well, but over the course of its development, aviation technology would forever alter how American conceptualized their own country.

## Invention
### Early Flight

The history of flight precedes recorded human history. From ancient times, to the frenzy of balloon flight in the 1700s, much of the history of flight has been unpowered, lighter-than-air flight. The 1800s saw the development of unpowered, heavier-than-air gliders. Glider technology directly set the stage for modern aircraft through the development of the curve airfoil wing. Sustained, powered, heavier-than-air flight, however, was realized in 1903. The Wright Brothers’ famous first flight went relatively unnoticed for several years after the fact. What attention it did receive regarded it as a hoax. The Wrights finally received a patent for their flier in 1906, and by 1908 has entered into a contract with the US Military for the development of military aircraft. Over the next three decades, propeller aircraft would increase in speed and comfort, but the world of aviation saw its next big change in 1940.

### The Jet Engine

Although jet engines were thought of as early as the 1920s, the first jet-powered aircraft did not make flight until 1937. The British and German militaries both utilized jet airplanes during World-War two. The first jet-powered aircraft for passenger use was the de Havilland DH 106, “the Comet”, developed in Britain in 1949. The first American passenger jet was the Boeing 707, which first flew in 1957 and had a top speed of 600 Miles per Hour.

## Early Market Development

The onset of World War One spurred aircraft development immensely. Military officials recognized the utility of planes for reconnaissance and offense. As with many technologies, early adoption by the military paved the way for aircraft to become integrated into civilian life. After World War One ended, the primary role of aircraft shifted from war machine to delivery tool. In May of 1918, the first airmail flight departed Washington, DC en route to New York City. The influx of money from US Airmail contracts allowed the industry to thrive through the Great Depression and to make significant technological strides throughout this era.
While the first flight carrying a paying passenger (St. Petersburg, FL to Tampa, FL, 23 Minutes, 1 passenger, 1 Pilot) took place in 1914, passenger aviation would not take off in a big way until the end of the Great Depression. From 1930 to 1944, the number of US domestic air passengers increased nearly 7-fold, from 1.1 Million to 7.4 Million. The growth rate of passengers remained relatively stable through the remainder of the tri-motor years, and rapidly increased again once jet-powered aircraft became widespread, in the mid-1960s.

## The Role of Policy in the Birthing Phase
### Civil Aeronautics Act

The Civil Aeronautics Act of 1938 served to establish federal regulation of many aspects of passenger aviation. The Act created the Civil Aeronautics Authority (Later the Civil Aeronautics Board) to oversee safety and economic development. The Act would establish the authority of the federal government to manage such aspects of civil aviation as fares, entry to market, and which airlines could serve which routes. This control would remain in effect until Deregulation in 1978.

### Military Contracts

The US military also had a significant hand in shaping the aviation industry. Although aircraft were used in World War One, the Second World War was when aviation came into its own as an industry. The US military acquired land all over the country for the development of airfields. Many of these airfields would later become, wholly or partly, passenger aviation terminals. This allowed for the widespread dispersal of infrastructure which enabled passenger aviation to be viable throughout the whole country, not just in communities which invested early on in land acquisition.
Many of these airfields served as training facilities for pilots, mechanics, and other aviation support industries. After the end of WWII, there was a surplus of persons trained with these skills, and the economy was strong enough to accommodate this surplus through expansion of air-based operations. Passenger operations expanded quickly in the post-war years, and airlines were able to fill their ranks with personnel who were already trained and experienced. This pattern also held true for personnel in the manufacturing sector.
As with many technologies, military support had far-reaching effects in the research and development departments. The most influential technology supported by the military during WWII was the jet engine. Developed shortly before World War II, in August 1939, the jet engine saw widespread use by many militaries during combat. Commercial applications would not begin until 1949, and, even then, not in earnest until the mid-1950s.

### Air Mail

The US government, through the use of air mail contracts, had significant effect on the face of the early aviation industry. The awarding of contracts could make or break a fledgling airline, and many of the companies which thrived throughout the 20th Century began with flying airmail routes. Even those airlines which provided service for passenger travel effectively subsidized this service by flying airmail routes. Passenger routes were not yet profitable, but airmail routes were government contracts and could cover the losses of passenger routes to ensure continued operation of airlines with these contracts.

## The Golden Age of Aviation

With the proliferation of the jet engine, commercial aviation was finally a competitive mode of travel. Propeller aircraft perform more efficiently at lower altitudes, which often experience more turbulence. They also produce more noise and were considered dirty by early passengers. Because jet engines are more efficient at higher altitudes, planes began to fly higher, which resulted in a smoother, less turbulent ride. Higher altitudes also allowed for increased speed, greatly decreasing the flight time between origins and destinations. The advent of the pressurised, enclosed cabin separated passengers from the noise and grime of engines. Flying became a glamorous mode of transportation, with attendant service, elaborate meals, and clever advertising.
The number of air passengers continued to growth through the middle of the 20th Century, surpassing 100 Million in 1965. By 1978, the year deregulation occurred, 250 Million passengers a year were travelling domestically within the United States.

## Deregulation

Over the course of its 40-year tenure, the Civil Aeronautics Board (CAB) had the authority to regulate even the most minute of details in the industry. From routes to fares to quality of service, the CAB controlled the airline industry. Throughout the 1970s, critiques of the CAB's practices began to emerge, and on 24 October 1978 the Airline Deregulation Act was signed into law. Deregulation affected all aspects of civil aviation except for safety. Entry to market, fares, and route service were all subject to market forces. Deregulation also allowed for the development of the now-standard hub-and-spoke route system, and the emergence of the low-cost carrier model.

### Hub-and-Spoke Systems

Prior to route deregulation, most airlines' route systems used a point-to-point system. A point-to-point system in one in which airlines operate direct flights between as many city pairs as possible. This is frequently inefficient for the airline and inconvenient for the passenger. A hub-and-spoke system is one in which airlines focus operations in a handful of cities, and operate connecting flights to and from these "hub" cities. This allows smaller markets to be served more often and more cost-effectively. While this offers more frequent service for many small markets, passengers often find transferring flights in unfamiliar cities to be stressful or confusing.

### The Low-cost Carrier Model

The low-cost Airline charge has largely been led by Southwest Airlines, one of the first to emerge nationally in the post-deregulation era. This model is defined by:
* Reliance on on-line resources for bookings and customer service
* Homogeneous fleet of aircraft to streamline and lower the cost of operations and maintenance
* Fewer on-board amenities
* Unassigned seating, which often results in a faster boarding process
* Looser hub-and-spoke system which offers more point-to-point service based on market demand
This model has proven to be popular with many air travellers, though some remain loyal to the tradition "legacy-carrier" model still in use by older carriers who operated pre-deregulation.

# Quantitative Analysis
## S-Curve Modelling
### Modelling

After Compiling Passenger data for domestic US passengers from 1926-1944 and 1954-2103 the data was analyzed using the following steps:
* Transform the data using Natural Log, so that regression can be run, using $Year=X$ and $Y=\ln \left({\cfrac {S(t)}{(K-S(t))}}\right)$
* Estimate the value of K, the peak of the system
* Run a regression analysis to determine the Slope, Intercept, and r$^2$ of the data
* Determine t$_0$, the inflection point, by calculating $Intercept/-Slope$
* Using the value of K which returns the highest r$^2$, calculate the equation of the s-curve, which shows predicted passenger loads
$S(t)=K/\left(1+e^{-b(t-t_{0})}\right)$
This gave the following results:
$S(t)=690,000,000/\left(1+e^{-0.13388(t-1984)}\right)$
| Variable | Value |
| Intercept | -265.64422 |
| Slope | 0.13388 |
| r$^2$ | 0.9362 |
| t$_0$ | 1984 |

## Analysis

The graph at right shows the number of US Domestic airline passengers from 1926 through 2013. The years 1926 to the mid-1940s can be considered the "Birth" phase of passenger aviation. This is the phase in which the technology is being most heavily developed, but is underutilized as a transportation mode. From the mid-1940s to the early 2000s can be considered the growth phase. This is the time during which the mode gains a significant share and explodes in popularity. This growth phase begins to slow in the mid-1980s, but continues to grow through present times. Recently, around 2010, the passenger aviation sector reached maturity. The maturity phase is marked by very slow growth and the continuation of existent conditions.
The graph in the section above shows actual passenger data as compared to passenger loads predicted by the S-curve model. This shows an idealized model of the growth of aviation as a mode of transportation. The actual data maps very strongly to the predicted data.

## Conclusion

The growth of passenger aviation through the course of the 20th Century has had considerable effects on the global economy, and on the way residents of the United States conceptualize their country. The technological advancements of aviation have slowed considerably since the 1950s, and recently growth has slowed as well. Unless significant advancements are made in some area of passenger aviation, whether it be speed, or comfort, or other, growth will remain slow, and eventually peak.

# References

* ↑ http://history.nasa.gov/SP-09-511.pdf
* ↑ Rust, Daniel L. Flying Across America: the airline passenger experience. Norman, OK: University of Oklahoma Press, 2009. Print.
* ↑ Rust, Daniel L. Flying Across America: the airline passenger experience. Norman, OK: University of Oklahoma Press, 2009. Print.
* ↑ Daly Bednarek, Janet R. America's Airports: Airfield Development, 1918-1947. College Station, TX: Texas A&M University Press, 2001. Print
* ↑ Lewis, W. David; William F. Trimble. The Airway to Everywhere: A History of All American Aviation. Pittsburgh: University of Pittsburgh Press, 1988. Print
* ↑ Rust, Daniel L. Flying Across America: the airline passenger experience. Norman, OK: University of Oklahoma Press, 2009. Print.
* ↑ http://history.nasa.gov/SP-09-511.pdf
* ↑ Sinha, Dipendra. Deregulation and Liberalisation of the Airline Industry: Asia, Europe, North America, and Oceania. Burlington, VT: Ashgate Publishing Limited, 2001. Print.
* ↑ Rust, Daniel L. Flying Across America: the airline passenger experience. Norman, OK: University of Oklahoma Press, 2009. Print.
* ↑ Ben-Yosef, Eldad. The Evolution of the US Airline Industry: Theory, Strategy, and Policy. Dordrecht, Netherlands: Springer, 2005. Print
* ↑ Rust, Daniel L. Flying Across America: the airline passenger experience. Norman, OK: University of Oklahoma Press, 2009. Print.
* ↑ Rust, Daniel L. Flying Across America: the airline passenger experience. Norman, OK: University of Oklahoma Press, 2009. Print.
* ↑ Ben-Yosef, Eldad. The Evolution of the US Airline Industry: Theory, Strategy, and Policy. Dordrecht, Netherlands: Springer, 2005. Print
* ↑ http://www2.census.gov/prod2/statcomp/documents/HistoricalStatisticsoftheUnitedStates1789-1945.pdf
* ↑ http://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/subject_areas/airline_information/air_carrier_traffic_statistics/airtraffic/annual/1954_1980.html
* ↑ http://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/subject_areas/airline_information/air_carrier_traffic_statistics/airtraffic/annual/1981_present.html
* ↑ http://www.rita.dot.gov/bts/acts/customized/table?adfy=1996&adfm=1&adty=2014&adtm=7&aos=0&artd=1&arti&arts&asts=1&astns&astt&ascc&ascp=1