After the eruption of the Pacific War, the USA established the China-Burma-India Theatre and began military co-operation with the Chinese fighting Japan. From 1942 to 1945, the USA rendered air assistance to China by establishing an American air force in China, delivering airplanes to the Chinese air force, training Chinese pilots, and transporting war materials by air to the Chinese. American air support played a significant role in defeating Japan. During that time disputes between the American and Chinese leaders arose over US air aid and air supply to China, which created Sino-US diplomatic tensions and a crisis in Sino-US military co-operation. There were several reasons for this: the different military goals and strategies of the USA and China, Stilwell's emphasis on the role of ground forces and his contempt for air power, the construction of the Ledo Road, and the lack of understanding of Chinese military politics. However, the Chinese demand for more US air support was justified and reasonable at that time. If American military and civilian leaders had had a better understanding of Chinese culture, including Chinese politics and the Chinese military, as well as the characteristics of Chinese leaders and others, both the Americans and the Chinese would have solved the problem of air support for China. It seems that the Sino-US dispute over air aid and air supply to China was not the fault of China or the USA nor of Stilwell or Chiang Kai-shek. It was inevitable in the circumstances.