Airlines follow a corporate structure where each broad area of operations (such as maintenance, flight operations (including flight safety), and passenger service) is supervised by a vice president. Larger airlines often appoint vice presidents to oversee each of the airline's hubs as well. Airlines employ lawyers to deal with regulatory procedures and other administrative tasks.[86]
Groups such as the International Civil Aviation Organization establish worldwide standards for safety and other vital concerns. Most international air traffic is regulated by bilateral agreements between countries, which designate specific carriers to operate on specific routes. The model of such an agreement was the Bermuda Agreement between the US and UK following World War II, which designated airports to be used for transatlantic flights and gave each government the authority to nominate carriers to operate routes. 

A corduroy or beach ladder (or board and chain) is an array of planks (usually hardwood or treated timber) laid close together and perpendicular to the direction of traffic flow, and secured at each end by a chain or cable to form a pathway or ramp over the sand dune. Corduroys are cheap and easy to construct and quick to deploy or relocate. They are commonly used for pedestrian access paths and light duty vehicular access ways. They naturally conform to the shape of the underlying beach or dune profile, and adjust well to moderate erosion, especially longshore drift. However, they can cease to be an effective access surface if they become buried or undermined by erosion by surface runoff coming from the beach head. If the corduroy is not wide enough for vehicles using it, the sediment on either side may be displaced creating a spoon drain that accelerates surface run off and can quickly lead to serious erosion. Significant erosion of the sediment beside and under the corduroy can render it completely ineffective and make it dangerous to pedestrian users who may fall between the planks.

The 1978 U.S. airline industry deregulation lowered federally controlled barriers for new airlines just as a downturn in the nation's economy occurred. New start-ups entered during the downturn, during which time they found aircraft and funding, contracted hangar and maintenance services, trained new employees, and recruited laid-off staff from other airlines.
Among the first countries to have regular airlines in Latin America and the Caribbean were Bolivia with Lloyd Aéreo Boliviano,[57] Cuba with Cubana de Aviación, Colombia with Avianca (the first airline established in the Americas), Argentina with Aerolineas Argentinas, Chile with LAN Chile (today LATAM Airlines), Brazil with Varig, Dominican Republic with Dominicana de Aviación, Mexico with Mexicana de Aviación, Trinidad and Tobago with BWIA West Indies Airways (today Caribbean Airlines), Venezuela with Aeropostal, Puerto Rico with Puertorriquena; and TACA based in El Salvador and representing several airlines of Central America (Costa Rica, Guatemala, Honduras and Nicaragua). All the previous airlines started regular operations well before World War II. Puerto Rican commercial airlines such as Prinair, Oceanair, Fina Air and Vieques Air Link came much after the second world war, as did several others from other countries like Mexico's Interjet and Volaris, Venezuela's Aserca Airlines and others.
The first French airline was Société des lignes Latécoère, later known as Aéropostale, which started its first service in late 1918 to Spain. The Société Générale des Transports Aériens was created in late 1919, by the Farman brothers and the Farman F.60 Goliath plane flew scheduled services from Toussus-le-Noble to Kenley, near Croydon, England. Another early French airline was the Compagnie des Messageries Aériennes, established in 1919 by Louis-Charles Breguet, offering a mail and freight service between Le Bourget Airport, Paris and Lesquin Airport, Lille.[10]
Beach nourishment involves pumping sand onto beaches to improve their health. Beach nourishment is common for major beach cities around the world; however the beaches that have been nourished can still appear quite natural and often many visitors are unaware of the works undertaken to support the health of the beach. Such beaches are often not recognized by consumers as artificial. A famous example of beach nourishment came with the replenishment of Waikīkī Beach in Honolulu, Hawaii, where sand from Manhattan Beach, California was transported via ship and barge throughout most of the 20th century in order to combat Waikiki's erosion problems. The Surfrider Foundation has debated the merits of artificial reefs with members torn between their desire to support natural coastal environments and opportunities to enhance the quality of surfing waves. Similar debates surround beach nourishment and snow cannon in sensitive environments.
In the 1950s, the De Havilland Comet, Boeing 707, Douglas DC-8, and Sud Aviation Caravelle became the first flagships of the Jet Age in the West, while the Eastern bloc had Tupolev Tu-104 and Tupolev Tu-124 in the fleets of state-owned carriers such as Czechoslovak ČSA, Soviet Aeroflot and East-German Interflug. The Vickers Viscount and Lockheed L-188 Electra inaugurated turboprop transport.
Service during the early 1920s was sporadic: most airlines at the time were focused on carrying bags of mail. In 1925, however, the Ford Motor Company bought out the Stout Aircraft Company and began construction of the all-metal Ford Trimotor, which became the first successful American airliner. With a 12-passenger capacity, the Trimotor made passenger service potentially profitable.[29] Air service was seen as a supplement to rail service in the American transportation network.
Moreover, the industry is structured so that airlines often act as tax collectors. Airline fuel is untaxed because of a series of treaties existing between countries. Ticket prices include a number of fees, taxes and surcharges beyond the control of airlines. Airlines are also responsible for enforcing government regulations. If airlines carry passengers without proper documentation on an international flight, they are responsible for returning them back to the original country.

The world's largest airlines can be defined in several ways. American Airlines Group is the largest by its fleet size, revenue, profit, passengers carried and revenue passenger mile. Delta Air Lines is the largest by assets value and market capitalization. Lufthansa Group is the largest by number of employees, FedEx Express by freight tonne-kilometers, Ryanair by number of international passengers carried and Turkish Airlines by number of countries served.


Beaches are often dumping grounds for waste and litter, necessitating the use of beach cleaners and other cleanup projects. More significantly, many beaches are a discharge zone for untreated sewage in most underdeveloped countries; even in developed countries beach closure is an occasional circumstance due to sanitary sewer overflow. In these cases of marine discharge, waterborne disease from fecal pathogens and contamination of certain marine species are a frequent outcome.
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