Tiltrotor aircraft having rotatable wing extensions with winglets

A tiltrotor aircraft having a VTOL flight mode, a forward flight mode and a conversion flight mode, the tiltrotor aircraft comprising:

• a fuselage;
• a wing supported by the fuselage having first and second outboard ends;
• and
• first and second pylon assemblies positioned, respectively, proximate the first and second outboard ends of the wing, each of the pylon assemblies comprising:
• a fixed pylon having an outboard end;
• a rotor assembly rotatably coupled to the fixed pylon, the rotor assembly operable to rotate between a vertical takeoff and landing orientation and a forward flight orientation, the rotor assembly including a proprotor operable to produce a slipstream;
• a wing extension rotatably disposed to the outboard end of the fixed pylon such that the rotor assembly and the wing extension are separated by at least a portion of the fixed pylon, the wing extension having a forward edge and an outboard end;
• and
• a winglet coupled to the outboard end of the wing extension, the winglet having a forward edge;
• wherein, the wing extension and the winglet are configured to rotate in synchrony with the rotor assembly such that the forward edges of the wing extension and the winglet remain in the slipstream of the proprotor.