In World War 2 in which aspect did Canada contribute more to Allied air effort than any other Commonwealth country?

During World War II, Canada contributed more to the Allied air effort than any other Commonwealth country primarily through its training programs. The British Commonwealth Air Training Plan (BCATP), established in 1939, trained hundreds of thousands of aircrew from various Allied nations, providing essential pilots, navigators, and support personnel. Canada's expansive geography and resources allowed for the establishment of numerous training facilities, significantly bolstering the Allied air capabilities throughout the war. This effort was crucial in meeting the high demand for skilled aircrew needed for various operations.