Operation Bolero

Operation Bolero was the commonly used reference for the code name of the United States military troop buildup in Great Britain during World War II in preparation for the initial cross-channel invasion plan known as Operation Roundup. ("Bolero" was the code name used in official communications to stand in for "United Kingdom" when describing the theater or movements.) What later became the Bolero plan - the buildup of a strategic air force in Great Britain in preparation for Roundup - was first submitted by Commanding General of the U.S. Army Air Forces Henry H. Arnold to General George C. Marshall on April 12, 1942, and set in motion a huge movement of men and material that laid the groundwork for Operation Overlord.

To complement the Roundup invasion plan, planning for the movement and basing of U.S. forces in the UK was begun at the end of April 1942 and given the code name of Bolero. A combined committee of key British and American logistical officers worked in both Washington, D.C. and London planning the build-up, to co-ordinate the effort on the highest level.

In May 1942, with a tentative target date for Roundup of April 1943, the Operations Division of the War Department and USAAF Headquarters drafted plans to transport and house a million U.S. troops: 525,000 ground troops, 240,000 air force troops, and 235,000 from Services of Supply. Arnold's plan to Marshall called for the basing by April 1, 1943, of 21 heavy bomb groups (B-17 and B-24), 8 medium bomb groups (B-26 and B-25), 9 light bomb groups (A-20), 17 fighter groups (P-38, P-39, P-40, and P-47), 6 observation groups, and 8 transport groups--a total of 69 combat groups plus their service units.

General Arnold met with RAF Air Chief Marshal Charles Portal at the end of May 1942 and presented the US schedule for the arrival of U.S. Army Air Forces into the theater by March 1943, totalling 3,649 aircraft. The proposed build-up anticipated 15 groups in July, 35 by November and 66 by March, excluding observation squadrons. General Arnold anticipated that by the April 1 deadline, the combat units of the Eighth Air Force would have 800 heavy bombers, 600 medium bombers, 342 light bombers, and 960 fighters. (At the time the actual strength of the Eighth in the United Kingdom was 1,871 troops and no aircraft).