Since their early use for primitive ISR and combined operations, UAS have developed into increasingly multipurpose instruments performing a wide array of missions (from limited strike operations, search and monitoring to time-sensitive targeting) and offering new maneuver options to the armed forces. These improvements in range, speed, endurance, situational awareness and payload, achieved through adaptive use of new information technologies, were catalyzed by the Afghanistan and Iraq testing grounds that proved critical in breaking institutional resistance. Yet for all their contribution to the shaping of a quick learning curve, these developments have occurred in permissive airspace. After tracing back the history of UAS development, this paper argues that the US can overcome the different challenges to UAS brought by contested and denied airspace, as traditional power threats constrain force projection through A2AD strategies. To increase their force multiplier potential, the US will likely improve UAS capabilities in stealth, evasiveness, maneuverability and automation, strengthening both air and sea power.Since their early use for primitive ISR and combined operations, UAS have developed into increasingly multipurpose instruments performing a wide array of missions (from limited strike operations, search and monitoring to time-sensitive targeting) and offering new maneuver options to the armed forces. These improvements in range, speed, endurance, situational awareness and payload, achieved through adaptive use of new information technologies, were catalyzed by the Afghanistan and Iraq testing grounds that proved critical in breaking institutional resistance. Yet for all their contribution to the shaping of a quick learning curve, these developments have occurred in permissive airspace. After tracing back the history of UAS development, this paper argues that the US can overcome the different challenges to UAS brought by contested and denied airspace, as traditional power threats constrain force projection through A2AD strategies. To increase their force multiplier potential, the US will likely improve UAS capabilities in stealth, evasiveness, maneuverability and automation, strengthening both air and sea pow