The 1945 Japan–Washington flight was a record-breaking air voyage made by three specially modified Boeing B-29 Superfortresses on September 18–19, 1945, from the northern Japanese island of Hokkaidō to Chicago in the Midwestern United States, continuing to Washington, D.C.

Originally intending to fly 6,500 miles (10,460 km) nonstop to Washington, D.C., the airmen encountered unexpected headwinds over Alaska Territory and Canada, and they predicted that two of the aircraft would not have enough fuel to take them the full distance.

All three B-29s landed in Chicago instead, refueled, and continued to Washington, where each crewman was awarded the Distinguished Flying Cross, including the three pilots: Generals Barney M. Giles, Emmett O'Donnell Jr. and Curtis LeMay.

In a ten-day process that continued as a typhoon raged off Okinawa, the aircraft was stripped of unnecessary equipment such as armor and gun turrets, and the resulting empty spaces in the fuselage were faired over with smooth metal to minimize parasitic drag.

Blister-type bubble windows were replaced with flat ones, painted group markings were removed, and the aluminum aircraft skin polished to a high luster, all in order to achieve the least possible drag.

[3] On September 15, the three aircraft left Iwo Jima, flying north past Okinawa, where the typhoon had blown itself out.

[2] During an interview for the Your AAF fifth episode titled "blind landings" broadcast 20 September 1945, General Lemay was asked about the length of the airstrip.

[2][3] It was built at the southern part of Japan's northern island Hokkaidō, near the city of Sapporo, as the base for long-range flights to attack the U.S.—one-way suicide trips made by four-engine bombers—a function that it never served.

[3] With that treatment setting the tone for U.S.–Japan relations in the area, the airmen made certain to wear side arms as they walked around downtown Sapporo on the evenings of September 16 and 17.

[2] The second aircraft's commander was Major General Curtis LeMay, Chief of Staff of the Strategic Air Forces.

Number 2, dubbed Marianna Belle by its combat crew, made the cut because it did not consume more than the normal amount of fuel and oil in carrying out its missions, which were marked by top mechanical reliability.

[3] The plan was for each aircraft to make its own way over the Kamchatka Peninsula at the eastern edge of the Soviet Union, then over the Bering Sea to Nome, Alaska, and continue over Fairbanks, over the Canadian Rockies and much of Canada, over the Great Lakes, then on to Washington, D.C. near the Atlantic coast—a total of 6,762 miles (10,882 km) taking 26 hours in the air.

[3] This distance would not have broken the world's distance record then held by two Royal Air Force Vickers Wellesley aircraft that had flown from Ismaïlia, Egypt, to Darwin, Australia, in 1938, covering 7,162 miles (11,526 km), but it was considered a good public relations stunt, good for the USAAF and the generals' images.

[3] With the airfield lit by truck headlamps, Number 1 commanded by Giles was first to take off, a little after 6:00 local time, as dawn began to glow in the east.

The heavily loaded machines required every bit of the 8,200-foot (2,500 m) concrete runway to get airborne—and some of the gravel beyond—reaching 142 miles per hour (229 km/h) before lifting from the ground.

"[2] Five hours out of Japan, the airmen in Number 2 were over Kamchatka when they were met by three Bell P-63 Kingcobra fighters wearing the red star insignia of the Soviet Air Force.

The Soviet fighter pilots inspected the unarmed B-29 at close range and then performed aerobatic maneuvers for the Americans.

[2] Wearing fur-lined flight suits did not prevent the men from feeling the extreme cold of high altitude.

At 7 am Eastern War Time, aircraft Number 2 was over Northway, Alaska, and navigator Bill Townes determined that they were behind schedule.

[3] Seventeen hours after lifting off at sunrise in Japan, the men began to see the sun rise again over the Yukon—it was a very short day for them, and none had been able to sleep for the excitement of the trip, the stimulant benzedrine, and the penetrating cold.

Though the B-29s had been delivered to the war front complete with deicing equipment, such gear had been removed months before to reduce weight and therefore increase combat range and speed.

[14] While the aircraft were refueled, newspaper reporters asked questions of Giles and of Captain Kermit Beahan, who as bombardier aboard Bockscar, had visually targeted Nagasaki in order to drop the second atomic bomb.

The "silvery sky giants, manned by their blue ribbon crews" flew over National Airport in formation at 9:30 pm and landed.

"[7] Other B-29 crewmen still in the Pacific Ocean theatre of World War II did not pay much attention to the record-breaking flight.

Harry Changnon of the 40th Bomb Group on Tinian said "most of us in the 40th knew little about the trip in September 1945 as we were busy preparing to fly our 45 B-29s home in October".