Unmanned aircraft systems have long held great promise for military operations, but technology has only recently matured enough to exploit that potential. Much as the stealth fighter and Patriot missile came to public attention during the 1991 Gulf War, surveillance and missile-attack operations by Predator unmanned aircraft have been well publicized throughout the more recent conflicts in Iraq and Afghanistan. The Department of Defense’s (DoD’s) 2012 plan calls for purchasing more of the existing unmanned aircraft systems for current operations, improving the systems already in service, and designing more-capable unmanned aircraft systems for the future. At the request of the former chairman of the House Committee on the Budget, CBO compared the costs of DoD’s plans and the capabilities those plans might provide for reconnaissance and light attack missions with the costs and capabilities of some alternative options. In keeping with CBO’s mandate to provide objective, impartial analysis, this study makes no recommendations.