The USAF is organized on a functional basis in the United States and a geographical basis overseas. A major command (MAJCOM) represents a major Air Force subdivision having a specific portion of the Air Force mission. Each MAJCOM is directly subordinate to HAF. MAJCOMs are interrelated and complementary, providing offensive, defensive, and support elements. An operational command consists (in whole or in part) of strategic, tactical, space, or defense forces; or of flying forces that directly support such forces. A support command may provide supplies, weapon systems, support systems, operational support equipment, combat material, maintenance, surface transportation, education and training, or special services and other supported organizations.