WHEN THE SUPERPOWERS FACED OFF IN THE AIR OVER KOREA, EACH SIDE WANTED WHAT THE OTHER ONE HAD. The U.S. Air Force was able to determine precisely how the Soviet-built MiG-15 compared with its own premier fighter, the North American F-86 Sabre, because on September 21, 1953, two months after the cessation of hostilities in Korea, North Korean Lieutenant No Kum-Sok defected, flying his MiG-15 to Kimpo Air Base, South Korea. (The pilot earned a $100,000 reward, and his aircraft is now on display at the U.S. Air Force Museum in Dayton, Ohio.) The next day, the Air Force airlifted the MiG to Okinawa and sent two test pilots—Major Charles “Chuck” Yeager and Captain H.E. “Tom” Collins—to take its measure. During 11 test flights, the two pilots answered a question that is still being asked 50 years later: Which is better, the Sabre or the MiG?

At the start of the Korean War, the F-86 was the fastest airplane in the world: Its maximum speed was a blistering 685 mph. The MiG, at 670 mph, was not far behind. The Sabre had higher roll and turn rates than the MiG. But the test pilots found that the MiG had better acceleration, could climb faster, and could fight at a higher altitude.

With two 23-mm and one 37-mm cannon, the MiG packed a harder punch than the Sabre’s six .50-caliber machine guns. But the Sabre had sharper aim. Its AN/APG-30 radar gunsight gave its pilots the advantage in ease of use and accuracy.

The Soviets had learned all this even before the Americans did. They had conducted comparisons of their own, thanks to a rare combination of circumstances and a focused opportunism.

Although U.S. Air Force Second Lieutenant Bill N. Garrett didn’t know it at the time, the MiG-15 that took him out of the fight on October 6, 1951, was flown not by a Chinese or North Korean pilot, but by a Russian. The MiG pilot had hit Garrett’s F-86A behind the cockpit and had damaged its J-47 engine and ejection seat. As Garrett struggled westward toward the Yellow Sea, where he planned to ditch and, with luck, get rescued, another MiG pilot spotted his stricken aircraft. This pilot too was Russian.

Throughout the Korean War, U.S. pilots traded rumors about the enemies they faced in the air; they were never briefed that they were flying against Soviet pilots, but they suspected as much. What U.S. pilots didn’t know was that every MiG flown in North Korea between November 1950 and December 1951 had a Soviet pilot at the controls. They didn’t know that a veteran Soviet unit, the 324th Fighter Air Division, had arrived in China in April 1951. They didn’t know that the ranks of the 324th were filled with some of the highest scoring Soviet pilots from World War II or that by October those pilots would down so many B-29s that the U.S. Far East Air Force would have to restrict the big bombers to night missions. And Garrett didn’t know that a pilot of the 324th was following him to finish him off.

Captain Konstantin Sheberstov was patrolling in a formation of four when he spotted easy prey: a lone, wounded F-86. Sheberstov remembered the incident 45 years later for the Russian aviation journal Mir Aviatsii: “This F-86 was descending at an angle of 45–50 degrees with black smoke [trailing]. I started chasing him at the maximum speed. I caught up with him at an altitude of [3,300 feet] and from a distance of [975 to 1,150 feet] opened fire….” In trying to evade his pursuer, Garrett lost more altitude and was barely able to reach the mud flats along the coast, where he ditched the airplane. Here, on October 6, 1951, the Russians were presented with the trophy they had been trying to snare for months.

In the month before the first F-86s got to Korea, MiGs ruled the sky. Although World War II F-51 Mustangs were holding their own, they were no match for the Russian-built jets, and the U.S. straight-wing jets, Republic F-84s and Lockheed F-80s, were almost 100 mph slower than the MiG-15. But in December 1950 the Sabre arrived, like a Hollywood sheriff come back to town; they had barely joined the war when they shot down six MiG-15s in a single engagement on December 22.

The Soviets immediately set out to learn everything they could about the new enemy fighter. In the months that followed, Soviet intelligence agents monitored F-86 radio transmissions, interrogated Sabre pilots who had been shot down and taken prisoner, and reported their findings to the Soviet leadership. Premier Joseph Stalin himself gave the order to capture an F-86.

How the Soviets first attempted to carry out the order is not a proud moment in Russian aviation history. In April 1951, the Soviet Central Aero-Hydrodynamics Institute, a flight research center located at what is today Zhukovsky Airfield near Moscow, dispatched a special group of test pilots to a training base in Manchuria. The team practiced precision formation flying in MiGs, with the outlandish goal of boxing in an F-86, escorting it to Manchuria, and somehow forcing it to land. After a month of practice, the pilots joined the 196th Fighter Air Regiment, part of the 324th Fighter Air Division, at Andun, on the Manchurian side of the Yalu River, which formed a border between China and North Korea.