The United States Transportation Command (USTRANSCOM) is one of the eleven unified commands of the United States Department of Defense. In both times of peace and war, USTRANSCOM's role is to provide the Department of Defense with air, land, and sea transportation. USTRANSCOM was founded in 1987 and is based at Scott Air Force Base in Illinois.

A unified combatant command, also referred to as a combatant command (CCMD), is a joint military command of the United States Department of Defense that is composed of units from two or more service branches of the United States Armed Forces, and conducts broad and continuing missions. There are currently 11 unified combatant commands, and each is established as the highest echelon of military commands, in order to provide effective command and control of all U.S. military forces, regardless of branch of service, during peace or during war time. Unified combatant commands are organized either on a geographical basis or on a functional basis, e.g., special operations, force projection, transport, and cybersecurity. Currently, seven combatant commands are designated as geographical, and four are designated as functional. Unified combatant commands are "joint" commands and have specific badges denoting their affiliation.