United States

While there were 26 members of the United Nations in World War II, only the "Big Three" — United States, Great Britain, and Soviet Union — had indigenous aircraft industries during the war. The French had had their own aircraft industry, but French planes played only a minor part, since France was occupied for virtually all of the war.

The United States is my home country, had the largest publishing industry during the war, and had a copyright policy that makes it possible to restore period articles, so US planes will be the primary focus of this site. US-built planes were, predictably (because of availability of information, access to primary sources, and interest among readers), the planes most frequently and most thoroughly covered in the US press. US planes are described and discussed here as separate entities.

United Kingdom

The primary Ally was the United Kingdom, at the time a world-spanning empire. Canada, Australia, New Zealand and South Africa all participated, along with Cyprus and British India. Of these, Canada and Australia had aircraft industries that contributed significantly to the war effort. In this context, all members of the United Kingdom are lumped together as British.

In the early stages of the war, British planes were more advanced in terms of combat-ready design elements than US planes were. Britain, however, rapidly ran up against the limits of their manufacturing capacity. Prewar orders from Great Britain and France (and a few other nations) went a long way toward preparing the US manufacturing base for the massive buildup that took place between 1939 and 1943. Douglas DB-7 Bostons (became A-20 Havoc), Curtiss Tomahawk (P-40), Grumman Martlet (F4F Wildcat), Consolidated Liberator (B-24 Liberator), Boeing Fortress (B-17 Flying Fortress), North American Mustang (P-51 Mustang) all were produced for British and French (impounded when France fell) orders in much larger quantities than had previously been the order rate. This allowed the manufacturers to identify and correct various difficulties and bottlenecks in production processes. They also provided much-needed funding toward the expansion of capacity. In return, feedback from the front lines allowed design and incorporation of modifications that would make the planes more effective as tools of combat.

Through Lend-Lease, both the British and the Soviets (or Russians — the terms were used interchangeably) flew a lot of American-designed and -built planes. Those planes are addressed here as US planes, even though their use was by a foreign power. The British flew all the planes mentioned above and quite a few others. The Soviets got much of their mileage out of P-39s, B-25s and A-20s. And, of course, everyone who could used the incomparable C-47.

Of British planes, the Bristol Beaufighter and de Havilland Mosquito got detailed Design Analysis articles — and a lot of other coverage, especially of the Mosquito.
Other British planes got less complete coverage, but enough to warrant their own links here:

There were also articles on the British and Commonwealth war effort:

Soviet Union

Soviet attitudes toward the West were, even then, untrusting, so much less information was available on Soviet aircraft type and usages was available to the American press. For the most part, Soviet coverage consisted of survey articles, pieces on operational units and actions, and propaganda pieces on Soviet manufacturing.

China

Of course, not all of our allies were involved in the European war. Apart from the Commonwealth nations, which I lump together with British, there were the Chinese, who had large land forces, a country partly occupied by the Axis, and a compelling need for air forces. China had no significant indigenous aircraft industry. Nearly all aerial action over China and in the CBI theater (China-Burma-India) generally was between US and Japanese aircraft, though there was some contribution by British planes, too.

Other Allies with aircraft industries

Brazil and Mexico had relatively small indigenous aircraft industries.

Occupied Allies

Belgium, Czechoslovakia, Denmark, France, Greece, Luxembourg, Netherlands, Norway, Poland, and the "associated state" of the Philippines were all essentially governments in exile. Yugoslavia was a battleground state, nominally occupied territory. None were in a position to supply airframes to the war effort. Both the French and Dutch aircraft industries were absorbed the the German war effort, but primarily as manufacturers of German machinery.

Other Allies

Costa Rica, Cuba, Dominican Republic, El Salvador, Guatemala, Haiti, Honduras, Nicaragua, and Panama were signatories to the original Declaration by United Nations. None contributed significant aircraft types.

Turkey formally joined the Allies late in the war, but ended up on the right side.