From Japan Runs Wild, 1942–1943, by Peter Harmsen (War in the Far East, Book 2; Casemate, 2020), Kindle pp. 104-105:
The United States retained high hopes for China’s potential, and for the overall importance of what was known as the China-Burma-India Theater. From early 1942, large numbers of American personnel were sent to the region, primarily India. Given the conditions, a world at war, moving from one theater to another was a drawn-out affair. The China specialist John Paton Davies Jr, who was assigned as political attaché to Joseph Stilwell, described the 13-day trip from New York to Calcutta: “We flew by one of Pan American’s original clippers, a flying boat, to Belém at the mouth of the Amazon—moist, mossed, suffocating, hyper-tropical—then Natal, and across the Atlantic to somnolent Fisherman’s Lake in Liberia. The remainder of the trip was by two-engine C-47 transport planes to Kano and then Maidugiri, both in Nigeria, across the scrubby wilderness of Chad to Khartoum dominated by the Nile, up to Cairo, swarming with handsome British staff officers whom the troops called the gabardine swine, over to Tel Aviv, down to Shatt-al-Arab, carrying the mingled waters of the Tigris and the Euphrates, out above the azure-emerald Persian Gulf to Sharjah’s desert airstrip manned by an RAF ground crew of a forlorn half dozen and a gazelle, along the desolate, jagged coast of Iran and Baluchistan to Karachi, and finally trans-subcontinentally to teeming, beholy-cowed Calcutta.”
The main priority for the United States was to keep China and its vast manpower resources in the war. Since the late 1930s, one of the main routes for keeping China supplied from the outside world had been the Burma Road, linking Burma to Chiang Kai-shek’s landlocked government in southwest China. “Though maladministration and corruption had reduced its inherently low capacity,” according to the official US history of the China-Burma-India theater, the road had for years “had great symbolic value as China’s last tie with freedom.” It had been built by hand for more than 700 miles through inhospitable terrain by tens of thousands of workers and had proved an invaluable asset, even though it had been closed briefly in 1940 by the British government, bowing to Japanese pressure.
By the time of the US entry into the war, the Burma Road was again in operation, and it had to be constantly maintained, again with the help of China’s most abundant economic resource: manual labor.