Under the leadership of aviation pioneer Juan Trippe, Pan Am expanded throughout Latin America ... and then around the world.

First came a fleet of flying boats ... the legendary Pan Am Clippers ... and then, after World War II, bigger airliners, and eventually, jets.

Pictured at left: The Flying Clipper S-42, built by Sikorsky for Pan-American Airways, rides the waters of Long Island Sound during tests near Bridgeport, Conn., March 30, 1934. The Clipper was used on Pan American's South American service. The hull of the 38,000-pound plane was 76 feet long, and its wing span 114 feet 2 inches.

Pan Am's Bermuda Clipper, c. 1937. The flying boat was used on the Baltimore-to-Bermuda route.

Pan American's Dinner Key Terminal and Airport. The Biscayne Bay, Fla., terminal was originally built as a Navy station, then transitioned to commercial use in the late 1920s and developed by Pan Am in the '30s as a key embarkation point.

The Pan American Martin M-130 "China Clipper" speeds out from San Francisco Bay in a test flight over the Pacific Ocean before inaugurating the first trans-Pacific passenger service in Nov. 1935, flying from San Francisco to the Orient.

The giant Pan American flying boat "Yankee Clipper" arrives in Southampton on April 4, 1939. The aircraft made history, bringing across the Atlantic the largest number of people ever carried in the flying boat.

The Anzac Clipper, one of the Boeing B-314s that Pan Am flew just prior to America's entry into World War II.

During the war, most of Pan Am's fleet of flying boats were transitioned to use by the military. The airline decided not to repurchase them once the war had ended. By the 1950s they were out of service.

A Pan Am Clipper seaplane c. 1941.

Pan American Airway's "Yankee Clipper" in 1943.

An interior view of a Pan Am airliner, when commercial air travel was definitely not "no frills."

Cabin service on board a Pan American airliner.

A Pan American long-range Super-7 Clipper, seen on a training flight before going into service, July 26, 1956.

A Pan American World Airways Boeing 707, with crew and 39 passengers, is serviced after a flight from Baltimore to Brussels, Belgium, Oct. 17, 1958. The 707 inaugurated American trans-Atlantic jet passenger service, completing the 3,910-mile flight in 7 hours, 15 minutes.

An undated photo of a Pan American Airliner DC-8 Jet Clipper, which began seeing service in 1958.

The DC-8 Jet Clipper, capable of nonstop trans-oceanic flights, cruises at 575 miles per hour and is powered by four Pratt and Whitney JT-4A, J-75, jet engines rated at 17,000 pounds of thrust each. It has a fuel capacity of nearly 22,000 gallons and can carry 168 passengers in all-economy class seating arrangement.

A Pan American World Airways Boeing 707 turbo-jet airliner lands at London Airport in England on Sept. 8, 1959.

The Pan Am B-707, carrying 10 crew members and 23 passengers from New York, was the first American-built jet airliner to land in Britain.

At its height in the 1960s, Pan Am was America's unofficial flag carrier to the rest of the world.

The Beatles flew Pan Am on their first trip to the United States. At left: John Lennon, Paul McCartney, Ringo Starr and George Harrison arrive at New York's Kennedy Airport on Feb. 7, 1964.

The airline basked in the glow of '60s jet set glamour - as captured in Steven Spielberg's "Catch Me If You Can" (2002), starring Leonard DiCaprio. The film told the true story of Frank Abagnale Jr., a con man who - before he even turned 19 - impersonated an international pilot.

A future that wasn't quite to be: The Pan Am clipper ship sailing to an orbiting space station in Stanley Kubrick's "2001: A Space Odyssey" (1968).

A family picture taken on January 13, 1970 of the aircrew of the first commercial flight of the Boeing 747 from New York to London for Pan American. The Boeing 747 "Jumbo Jet" entered service on January 21, 1970, on Pan Am's New York-London route.

In this undated photo a helicopter lands on the roof of the Pan Am Building (now the Met Life Building) in New York City. The building was designed by Walter Gropius.

A helipad accident in 1977 in which five people were killed (including a pedestrian on the ground) ended the rooftop service.

The Pan Am Boeing 747 "Clipper Young America," c. 1970.

A Pan Am Boeing 747 flying over snow-covered mountains.

By the 1970s some very down-to-earth troubles were clipping the wings of the Pan Am clippers. The energy crisis hit the airline hard, and with virtually no domestic routes until the 1980s, Pan Am found itself at a tough competitive disadvantage.

A Pan Am Airlines Boeing 747-100 jet in flight, June 1, 1984.

The first flight of Pan American World Airways' advanced-technology L1011-500 tri-jet was made November 16, 1979.

A policeman walks away from the cockpit of the 747 Pan Am airliner that exploded and crashed over Lockerbie, Scotland, December 22, 1988. The Pan Am flight was on route for New York with 259 people on board. All 243 passengers and 16 crew members were killed, as well as 11 Lockerbie residents on the ground. In 2003, Libya admitted responsibility for the deaths of the 270 victims of the bombing of Flight 103.

The terrorist bombing took its own heavy toll on the faltering airline.

After years of downsizing and selling off assets, Pan Am declared bankruptcy in early 1991 ... and after eleven more months stopped flying for good.

Through licensing of the familiar name and logo, the Pan Am brand was resurrected after 1991, though the carriers were not related to the original airline. At left: A Pan Am Airbus A300-B4 jet on the tarmac at JFK International Airport in New York, September 25, 1996.

The latest incarnation of the brand, Pan American Airways, Inc., began cargo-only flights in November 2010, but intends to introduce passenger service.