War on the Asian Mainland Until late in the war, operations against the enemy on the Asian mainland in the China-Burma-India (CBI) Theater, were hindered by a tangled chain of Allied command, the long distance from sources of resupply and the very low priority of men and material given to the theater. The primary purpose of the Allied efforts in the CBI Theater was to hold the Japanese in check while achieving victory elsewhere. By mid-May 1942, the Japanese had driven to the borders of India, taking all of Burma and cutting the Burma Road into China. Only the arrival of the monsoon season prevented an invasion of India. During the enemy's rapid advance through Burma, Allied combat airpower consisted of a meager force of British Royal Air Force units, the American Volunteer Group (Flying Tigers) and fewer than a dozen USAAF B-17s and LB-30s (export version of the B-24) assigned to the newly created 10th Air Force. A trickle of reinforcements arrived from the U.S., and AAF bombers succeeded in flying a few bombing missions against the enemy, but they were unable to halt the Japanese advance. As Allied defenses crumbled in Burma, AAF transport crews aided in the evacuation of personnel and dropped supplies to the remnants of Lt. Gen. Joseph Stilwell's command as they retreated on foot. In June all of the 10th Air Force's bombers were transferred to Africa to bolster defenses there, temporarily leaving the AAF in India without a single operating combat unit. Click on the following links to learn more about the war on the Asian mainland. The "Hump": Lifeline to China Burma Campaign China Operations Allied Counteroffensive Development of the Boeing B-29 Brig. Gen. Clinton D. "Casey" Vincent Click here to return to the World War II Gallery. Find Out More Related Fact Sheets 14th Air Force in China: From Volunteers to Regulars Boeing B-17G Flying Fortress Consolidated B-24D Liberator Note: The appearance of hyperlinks does not constitute endorsement by the National Museum of the USAF, the U.S. Air Force, or the Department of Defense, of the external website, or the information, products or services contained therein.