A tiltrotor aircraft includes a fuselage supporting first and second wings each having an outboard end. First and second nacelles are respectively coupled to the outboard ends of the first and second wings. The first and second nacelles each have an outboard end. First and second wing extensions are rotatably coupled, respectively, to the outboard ends of the first and second nacelles. First and second actuators are operable to respectively move the first and second wing extensions to dampen a mode of the first and second wings, thereby stabilizing the tiltrotor aircraft.