Pan American World Airways (Pan Am) was the principal international airline in the United States for the majority of its existence and the nation's only international carrier before World War II. Pan Am was originally founded as Pan American Airways in 1927 as an international carrier only. Company founder and president Juan Terry Trippe (1899-1981) was a former World War I naval aviator. Trippe secured a contract to fly mail between Key West, Florida, and Havana, Cuba, in 1927. The airline's first passenger service between the two cities began the following year.

The first small planes soon gave way to larger craft, spanning longer distances. During the 1930s, Pan Am added larger planes to its fleet and expanded its passenger routes further afield. The newer planes were known as "flying clippers" because they landed on water. The flying boats included lounges, dressing rooms, and sleeping berths. In 1937, Pan Am secured contracts to commence transatlantic flights.

By the 1950s, Pan Am offered "around-the-world" service, and its brand was as familiar abroad as Coca-Cola. In 1955, Pan Am placed an order for twenty Boeing 707 aircraft, becoming the aircraft's launch customer. In 1966, eleven years after the first Boeing 707 order, Pan Am became the launch customer for the Boeing 747 aircraft.

Trippe retired in 1968, which affected the health of the company. Pan American World Airways, like many in the industry, was impacted by the oil crisis of the 1970s when the Organization of Arab Petroleum Exporting Countries (OAPEC) proclaimed an oil embargo, causing the price of jet fuel to skyrocket. Being reliant on high-priced foreign fuel, Pan American Am began experiencing financial difficulties.

The Airline Deregulation Act of 1978 allowed airlines to set their own fares and routes to keep the market competitive. The major airlines could now expand their routes and develop their own "express" commuter services. In its first attempts after deregulation to acquire domestic routes, Pan Am acquired National Airlines, a Miami-based network, but it overpaid due to a bidding war. Although initially revenues increased, so did fuel costs and other expenses. The venture was unsuccessful.

The company's health was on the rise, as was that of the aviation industry as a whole, until August 1985. Once again, a series of events impacted the entire industry. In August 1985, there were 2,010 fatalities in commercial aviation accidents, which was the worst single month in aviation history. Passenger sales for September through December 1985 plummeted due to negative press and flight anxiety.

On December 21, 1988, a bomb aboard Pan Am Flight 103, Boeing 747, en route from New York City to London, exploded over Lockerbie, Scotland, killing 270 people (259 people aboard, eleven people on the ground). The bereaved families sued for more than $300 million over a lack of security screening measures, and the Federal Aviation Administration fined the company for security failings. Pan Am continued to lose money from reduced passenger bookings and cancellations.

On January 8, 1991, Pan American World Airways filed for Chapter 11 bankruptcy protection. It was the third major airline to shut down in 1991, the other two being Eastern Air Lines and Midway Airlines. The company was subsequently dissolved and liquidated.