The Department of Defense (DOD) has continuing efforts to modernize its airlift and tanker fleets by investing billions of dollars to modify legacy airlift systems, such as the C-5 and C-130, and procure new aircraft, such as a tanker replacement. Acquisition has been on GAO's list as a high risk area since 1990. Past GAO reports, including two recently issued, raise concerns about the quality of analyses underpinning the programmatic decision-making surrounding DOD's airlift requirements. GAO has reported that elements contributing to a sound business case for an acquisition are missing or incomplete as DOD and the services attempt to acquire new capabilities. Those elements include firm requirements, mature technologies, a knowledge-based acquisition strategy, a realistic cost estimate, and sufficient funding. Acquisition problems that include failure to limit cost growth, schedule delays, and quantity reductions persist, but fiscal realities will not allow budgets to accommodate these problems any longer. This testimony addresses (1) the analyses supporting the Department of Defense's (DOD) mobility capabilities and requirements and (2) actions that are needed to improve the outcomes of weapon system acquisitions.