Pan American World Airways (Pan Am) operated from 1927 to 1991, when it faced bankruptcy and transferred much of its assets to Delta Air Lines. A review of Pan Am's fleet history is a fascinating look at the growth of US aviation over those years. The airline has operated a long list of the largest aircraft of the times, from the amazing flying boats up to 747 jumbos.

Pan Am and the flying boats

The airline started service in 1927, operating mail and passenger services between the US (starting in Florida) and Cuba - followed soon by other Central and South American destinations. Its first aircraft for this were Sikorsky flying boats. Flying boats were a significant development in aviation at the time. With airports still very limited, they could land or take-off from any large body of water.

Pan Am operated the Sikorsky S-36, S-38, S-40 and S-42. The S-40 introduced the famous 'Clipper' names that the airline continued to use into the jet age. Pan Am was the main airline user of these amphibious flying boats and the only operator of the S-40 and S-42.

It was also the only airline to operate the Martin M-130 flying boat, with three aircraft - named China, Hawaii, and Philippine Clippers. This was specifically designed for Pan Am, with the range and payload needed for its transpacific flights.

Pan Am had a long relationship with Sikorsky for these early aircraft, but Boeing was added in 1938. Pan Am purchased nine Bpeing 314 flying boats (out of a total of 12 built by Boeing).  The first six Clippers – Honolulu, California, Yankee, Atlantic, Dixie, and American were delivered throughout the first half of 1939. The next aircraft – Pacific, Anzac, and Cape Town – were designated as 314A and had larger fuel tanks and upgraded engines.

The 314s are remembered as luxurious and glamourous aircraft. Seating was arranged in a series of separate compartments, and there was a separate dining room and spacious bathrooms. It remained in service until 1951, having been used during the war years for military transport.

Introducing propellor aircraft

Pan Am used a few early propeller aircraft alongside its flying boats during the early years - including early Fairchild and Fokker aircraft. After the war though, the growth in airports and improvements in aircraft technology led to big changes.

The first big fleet shifts came with Douglas aircraft. The DC-2 was introduced in 1934, followed by the DC-3 in 1937. These gradually replaced the flying boats, with Pan Am going on to operate a total of 90 DC-3 aircraft, up to 1966. It also brought in the DC-4 from 1947 and the DC-6 and DC-7 after this. These formed the bulk of Pan Am's fleet throughout the 1940s and 1950s.

Douglas was not the only supplier for Pan Am, though. The relationship with Boeing continued, and it operated the Boeing 307 Stratliner and 377 Stratocruiser. Other major aircraft types during the 1940s and 1950s included the Convair CV-240 and CV-340 and the Lockheed Constellation.

Entering the jet age with Boeing

Boeing's early jet age moves were dominated by Boeing - but Airbus, Douglas, and Lockheed would follow later.

Pan Am was the launch customer for the Boeing 707 in 1958. The airline had worked closely with Boeing on its development. It operated eight of the original 707-120 variant and well over 100 of the later 707-320s.

The 707 was joined by the three-engine Boeing 727 in 1965, and Pan Am operated 46 727-100 and 105 727-200. The 707s were retired by 1981, but the 727s were still flying when the airline ceased operations.

The Boeing 747 was one of the most significant fleet additions. Pan Am again worked closely with Boeing on its development, with a vision for a new aircraft over twice the size of the 707. Pan Am was the launch customer for the 747-100 in 1970. It operated 47 of the first 747-100 variants, followed from 1974 by a total of 10 747-200s. It also operated 13 of the shortened, longer-range 747SPs.

Airbus, Douglas, and Lockheed jets

Pan Am is remembered by many for its large Boeing widebody fleet through the 1970s and 1980s and for its significant role as the 707 and 747 launch customer. Alongside the 707, Pan Am also ordered the Douglas DC-8. This entered service slightly later, in March 1960, and Pan Am operated 20 aircraft with the last retiring in 1971. It later added the DC-10 when it took over National Airlines in 1980.

And Pan Am also started a relationship with Airbus. It introduced the A300 in 1984 and the A310 in 1985 (operating 20 of these in total). It placed an order for the A320 family as well, but these were never delivered as the airline ceased operations. The first 16 aircraft built for Pan Am instead went to Braniff.

The airline also stuck with Lockheed and introduced the Lockheed L-1011 TriStar. The twelve aircraft passed to United Airlines when it acquired Pan Am's Pacific Division in 1986.

Pan Am also had supersonic ambitions. It was one of several airlines that place options for Concorde but never took delivery. It was also the first US airline to express interest in Boeing's supersonic 2707 project. This, of course, never happened, and the desire for supersonic receded over the next years.

End of service in 1991

Pan Am filed for bankruptcy in January 1991 and ceased operations in December. Several factors contributed, including the ongoing economic depression and increased competition in the market.

At the time of its collapse, Pan Am operated a Boeing-heavy fleet - much of it transferred to Delta Air Lines, which bought the remaining assets of Pan Am. The fleet in 1991 included:

• Boeing 727-200: 90 aircraft
• 747-100: 18 aircraft
• 747-200: seven aircraft
• 737-200: 16 aircraft
• A300: 12 aircraft
• A310: 19 aircraft
• There were also eight ATR 42 and 10 DHC Dash aircraft left in the Pan Am 'Express' fleet.

Pan Am has an important place in the development of long-haul flights. It operated many iconic aircraft. Feel free to discuss specific aircraft or the overall fleet strategy further in the comments.