Original: He had been the commander of the US China-Burma-India Theater in 1944–45 and he had a detailed knowledge of the World War II American airlift from India over The Hump of the Himalayas to China.
Simplified: He had been commander of the American forces in India and China in 1944 45. He knew about the Allied airlift from India over "The Hump" of the Himalayas to China.