All sides during the war prioritized the capture of intact enemy aircraft that were either airworthy or could be restored to airworthiness. The relative rarity of such aircraft made them too valuable to be used for ordinary combat missions. Most of these airframes ended up being used for technical evaluation or what would later be called aggressor training. The exceptions tended to prove the rule that enemy aircraft were too rare to risk.

Of the belligerents, it was the Germans who arguably made the most use of their captured aircraft. KG200, a specialist Luftwaffe wing, not only had a stable of German aircraft in its inventory, but also a number of Allied aircraft. Most of these Beute (the German term for war booty) planes were involved in the prosaic evaluation and familiarization roles, but a few did see service against their former owners. KG 200's B-17 were used periodically as long-range transports over enemy lines. While using an enemy aircraft though may have been a good cover when the Germans had lost air superiority, KG 200 and other Luftwaffe units more likely the American bomber for the simple reason that there was no equivalent long-range German transport. Other than the large and vulnerable Me-323, no other German transport aircraft could match the B-17 or other Allied bombers in terms of range. Neither the Ju-90 or its successors were reliable enough or available in large enough numbers to perform these missions and the FW-200 was also ill--suited for paradrops. Most of the B-17 transport missions tended to be routine air drops, often at night, and not terribly exciting. One of the few exceptions was Unternehmen Karneval (Operation Carnival) where a B-17 airdropped a commando unit into Belgium in 20 March 1945 where they made their way to the German city of Aachen and assassinated the American-appointed mayor, Franz Oppenhoff in 25 March. There were other long-range KG 200 missions, but parsing out when they used Allied aircraft is difficult because not only is their documentation fragmentary, the unit also used a variety of codes like Do-200/288 for these aircraft.

The Japanese captured a number of Allied aircraft in their initial conquests in the Pacific. Like their German allies, the Japanese were particularly impressed with the robustness and reliability of the B-17. A number of these aircraft were restored to airworthy status by Koku Gijutsu Kenkyujo (Air Technical Research Laboratory/ GiKen)in the home islands or Singapore. Some of GiKen's aircraft featured in propaganda materials, such as these B-17s. One of the more interesting uses of these captured aircraft was the 1944 film Kato hayabusa sento-tai which celebrated the IJA's Ki-43s, which in addition to blowing up models, featured captured Allied aircraft re-repainted to represent Allied aircraft. Osamu Tagaya has parsed out a more belligerent use for some of these aircraft in the defense of Rangoon. Apparently, a small detachment of three P-40Es were used in March 1943. This unit though accomplished little of note, except shooting down a Ki-21 by mistake.

Tagaya found out this nugget of information from Japanese memoirs and cross-referenced with surviving unit archives. Unfortunately, not all aviation historians are so diligent. There are numerous stories and yarns that got magnified in the retelling and were replicated by postwar writers. Perhaps the most famous of this is the tale of an Italian P-38 used to stalk Allied bombers. Martin Caidin told the story in his book Fork-Tailed Devil in which a Regia Aeronautica pilot Guido Rossi hunted down stragglers in his captured P-38. According to Caidin, Rossi's MO was to fly along side the bomber, request identification via radio. After a few victories, an American pilot borrowed a YB-40, a B-17 version heavily armed for escort, and painted a picture of Rossi's wife on the side. As Forked-Tailed Devil describes it:

On August 31, a B-17 raid struck Pisa. Fisher was flying among the bombers, and was actually damaged by enemy fighters. He recovered at a low altitude and had to feather two engines. Before lone, a lone P-38 was approaching and the crew was on high alert. Rossi, using very good English, contacted Fisher, just as he did on previous occasions. Rossi immediately noticed the nose art on the aircraft and spoke with Fisher. Fisher was still uncertain the pilot was Rossi and was chatting with Rossi normally. Fisher decided to bait this pilot to see if it was Rossi or not, and began talking about Gine and her location in Constantine. When Fisher was describing intimate details of their "relationship", Rossi lost his cool. He peeled off and began his attack. Fisher ordered all guns to open up on this P-38, and Rossi had to peel off trailing smoke. Rossi intended to ram the bomber, but began breaking up and could not maintain flight. He was able to ditch in the water and survived. Rossi was later picked up and taken prisoner. Fisher was awarded the Distinguished Flying Cross medal for his efforts. Fisher would survive the war, but was killed in a transport accident during the Berlin Airlift. Incidentally, Rossi was one of the mourners at his funeral.

While websites like Cracked.com have picked up Caidin's story and further replicated it, there are a number of holes in it. For one thing, there were no YB-40s in the MTO and there are no records of a Rossi in Italy. Furthermore, the chatter between aircraft does not really sit with established radio doctrine and stretches credibility. By the same token, making repeated attacks would have meant that the Italians either had a sizable stock of American ammunition or rearmed the P-38 with Italian weapons. The latter scenario is dubious because the P-38's weapons pod was an integrated component of the airframe; sticking a new gun into these mountings would have been tricky. The best aviation researchers have established is that the Italians did use a P-38 at Guidonia employed for evaluation purposes. It made one sortie in August 1943 where it might have shot down an American B-24, but was soon grounded for lack of specialized lubricants, spare parts, and fuel.

Caidin's tale has a whiff of veracity because there were persistent fears during the Allied air campaign that the Germans were using captured aircraft. The 8th AF did have daily mission markings applied in removable paint to prevent such interlopers from invading the bomber formations. It is possible that KG 200 and other units used their B-17s and B-24s to report on positions and radio work, but it is far more likely that such phantom bombers were just that, phantoms. Air combat is incredibly confusing and nerve-wracking. In such an environment, a straggler with its radio out or observing radio silence could easily become a Luftwaffe infiltrator to many observers.

The reality is that units like GiKen or KG 200 found that airworthy Allied aircraft were too rare to be wasted on routine missions. The few documented cases where they were impressed into service showed that this was often an unwise waste of a resource not easily replaced.

Sources

Lansdale, Jim. "Captured P-40." http://www.j-aircraft.com/captured/capturedby/p40warhawk/captured_p40.htm

Lerche, Hans-Werner. Luftwaffe Test Pilot: Flying Captured Allied Aircraft of World War 2. London: Jane's, 1980.

Thomas, Geoffrey J., and Barry Ketley. KG 200: The Luftwaffe's Most Secret Unit. Crowborough, East Sussex: Hikoki Publications, 2003.

One example of a scheme that almost came to be, happened in WW2. During WW2, Ian Fleming worked for British Naval Intelligence - after the war, Fleming became famous as the creator of James Bond. Anyways, at the time, the Allies were desperate to get hold of German encryption devices, which were known as Enigma machines. Fleming came up with the madcap scheme of taking a captured German Heinkel bomber and carrying out a fake emergency landing in the channel. The idea was that the Germans would send a Torpedo Boat to the rescue, and the Brits would then take over the E-Boat intact, with an enigma machine. Fortunately for all concerned, wiser heads prevailed and the mission was scrapped. The total insanity of this idea, gives some indication of how desperate things were in the early stages of the war.