AMC Space Available (Space-A) Travel is a Department of Defense (DoD) program that allows eligible personnel, such as retired service members, their dependents, and others in specific eligibility categories, to fly on Department of Defense aircraft for free or at minimal cost. Travelers occupy surplus seats that remain after all "Space-Required" passengers (those on official duty) have boarded. This travel is non-mission interference, meaning it cannot affect military operations, and travelers must be prepared for delays, have funds for commercial travel if needed, and have their baggage and other travel documents in order.