The Douglas World Cruisers were modified versions of DT-2 Navy torpedo planes and were powered by 12-cylinder Liberty engines reconditioned from Army Air Service stocks. They had dual controls and could be fitted with wheels and pontoons. (Photo: U.S. Air Force)

Three-quarter front view shows wings folded and engine without the cowling. The engine had two types of coolers: one for hot climates and a smaller one for arctic flying. (Photo: McDonnell Douglas Company)

Seven of the original World Flight crew members pose in their winter flying suits. Sgt. Arthur Turner, Sgt. Henry H. Ogden, Lt. Leslie P. Arnold (who replaced Turner), Lt. Leigh Wade, Lt. Lowell H. Smith, Maj. Frederick L. Martin, Sgt. Alva L. Harvey. Not shown: Lt. Erik H. Nelson and Lt. John Harding Jr. (Photo: U.S. Air Force)

Women sew cloth on wings of a World Cruiser. The work was pushed ahead rapidly so the planes could depart from Santa Monica on 15 March 1924. (Photo: McDonnell Douglas Company)

The Seattle (right) has had the pontoon installation completed before the official departure from Lake Washington, while the Chicago waits its turn. Wheels would not replace the pontoons until the planes reached Calcutta, India. (Photo: U.S. Air Force)

Major Martin and Sergeant Harvey at Kanatak, Alaska, after the Seattle had an engine failure. The U.S. Coast Guard rushed a new engine to them which they installed and resumed the flight. (Photo: U.S. Air Force)

Fuel and oil for the World Cruisers while in Alaskan waters was transported by U.S. Navy, U.S. Coast Guard, and a Bureau of Fisheries ship. Cooperation of these organizations was essential for the transit of the planes through the Aleutians to Japan. (Photo: U.S. Coast Guard)

Two views of the Seattle after it crashed into a mountain on the Alaskan Peninsula during the flight from Chignik to Dutch Harbor. Martin and Harvey suffered only minor injuries but the plane was totally destroyed. Years later, the engine and parts of the plane were brought to Anchorage and are on display at the Alaska Aviation Heritage Museum at Lake Hood. (Photo: U.S. Air Force)

Major Martin and Sergeant Harvey traveled for ten days after the Seattle crashed and found their way to a cannery at Port Moller on the Bering Sea side of the Alaska Peninsula. (Photo: U.S. Air Force)

The Chicago, Boston, and New Orleans are pulled up on the beach at Dutch Harbor to protect them from the frequently violent williwaws. (Photo: U.S. Air Force Museum)

Two ships that helped the World Fliers were (left) the U.S.S. Brookdale and the Eider, The Eider was provided by the U.S. Bureau of Fisheries. (Photo: Wade/Morrow Collection, U.S. Air Force Academy)

The World Fliers relax at the large Japanese naval air station at Kasumigaura while waiting for transportation to extensive welcoming activities in Tokyo. Nelson (holding map) confers with a Japanese naval officer about the route to Kushimoto, the next stop. (Photo: Wade/Morrow Collection, U.S. Air Force Academy)

Three of the four Cruisers are pulled up on the Resurrection Bay beach at Seward, Alaska, for protection from wind and high waves. En route to the next stop, the Seattle had engine failure and landed at Cape Igvak near Kanatak. (Photo: Wade/Morrow Collection, U.S. Air Force Academy)

Thousands of Chinese junks and sampans crowd the harbor at Shanghai, China. They posed a great danger when they deliberately crossed the takeoff paths of the planes. (Photo: Peter M. Bowers Collection)

The engine of the Chicago is changed at Hue, French Indochina (now Vietnam), with the help of American sailors under the supervision of Smith and Arnold. The bridge allows for the engine to be dropped into place. (Photo: U.S. Air Force)

Lts. Lowell Smith and Leslie Arnold wait for a boat to take them ashore at Saigon, then known as the “Paris of the Orient.” The crews were invited to several social events by the French and had to borrow white shirts and trousers from U.S. Navy officers. (Photo: Mobil Oil Company)

Erik Nelson and John Harding in the New Orleans nearly had a forced landing when an engine connecting rod broke splattering oil over the plane during the flight from Multan to Karachi, India. Nelson was able to nurse the plane for nearly an hour to a safe landing. (Photo: U.S. Air Force)

American sailors from the destroyer Hart assist the fliers at the Maidan, a large park in Calcutta, India (now Pakistan). Wheels replaced the pontoons here and the planes were overhauled. (Photo: U.S. Air Force)

The fliers were greeted by the largest crowd at Vienna, Austria, since leaving Japan but were able to stay only one night. Viennese of all ages pose happily for the camera. (Photo: U.S. Air Force)

Henry Ogden, promoted from sergeant to second lieutenant during the flight, completes filling the oil tank of the Boston at Le Bourget Airport in Paris. (Photo: U.S. Air Force)

The World Fliers met in Paris with Gen. John J. Pershing, leader of the Allied Expeditionary Forces during World War One. Left to right: Lts. Henry Ogden, Leslie Arnold, Lowell Smith, General Pershing, Lts. Leigh Wade, Erik Nelson, and John Harding Jr. (Photo: U.S. Air Force)

One of the World Cruisers flies formation with a British passenger plane en route from Paris to London. French planes escorted them to the English Channel. (Photo: U.S. Air Force)

A crowd surrounds the fliers and planes when they arrived at Croydon Airport near London. Many were American tourists who had departed at the same time from Paris and were allowed to greet the fliers. Others were restrained behind a fence at left. (Photo: U.S. Air Force)

The New Orleans is readied for towing through the streets of Reykjavik, Iceland, for maintenance with the help of sailors from the Richmond. (Photo: U.S. Air Force)

The New Orleans is towed through the streets of Reykjavik, Iceland, before an admiring crowd. The crews were surprised to find that the city was very modern and that most of the inhabitants could speak English. (Photo: U.S. Air Force)

The damaged Boston was towed to land until it became too dangerous. Wade made the decision to cut the tow lines from the Richmond loose and allow the plane to sink. Wade and Ogden would be given the prototype aircraft, named the Boston II, and permitted to join the other two planes at Nova Scotia. (Photo: U.S. Air Force)

A World Cruiser lands near an iceberg in the harbor at Frederiksdal, Greenland. The 830-mile flight from Reykjavik, Iceland, to Frederiksdal was the longest nonstop flight of the whole journey. (Photo: U.S. Air Force)

Seattle, New Orleans, and Boston II fly down the Hudson River to Manhattan and the New York harbor on 8 September 1924. They landed at Mitchel Field, Long Island, before a large crowd that included the Prince of Wales. (Photo: U.S. Air Force)

President Calvin Coolidge greets Lt. Leslie Arnold as Secretary of War John W. Weeks looks on. To the left is Herbert Hoover, who was then Secretary of Commerce. (Photo: U.S. Air Force)

Lowell Smith speaks at welcoming ceremonies at San Diego. The city claimed that the world flight started there, rather than at Santa Monica or Seattle. (Photo: Wade/Morrow Collection, U.S. Air Force Academy)

The single-engine New Orleans is parked beside a Pan American four- engine Boeing 707-321 after the intercontinental jet transport completed a world flight in 2½ days in 1959. The World Cruiser was borrowed from the Air Force Museum for a special event before being returned to Dayton in an Air Force transport. (Photo: Pan American World Airways System)

The small country of Monaco issued a stamp honoring the World Flight on the fortieth anniversary in 1964. A U.S. Postal Service committee turned down a commemorative stamp on the flight’s fiftieth anniversary as not being of sufficient public interest. (Photo: C. V. Glines)

President Calvin Coolidge (in raincoat) and Secretary of War John W. Weeks pose with five of the world fliers at Bolling Field, Washington, D.C., on 9 September 1924. (Photo: U.S. Air Force)

A rare photograph of the four World Cruisers on wheels after their christening at Seattle in April 1924. Shortly thereafter pontoons were attached and the Seattle crashed on a mountainside in Alaska. (Photo: U.S. Air Force Museum)

The Chicago passes a cargo ship along the east coast of North America before landing at Boston, where the pontoons were exchanged for wheels for the last time. (Photo: Wade/Morrow Collection, U.S. Air Force Academy)