Airframes configured for stable in-flight transition between forward flight and vertical takeoff and landing are described herein. In one embodiment, an aircraft can include a fuselage, opposed wings extending from opposed sides of the fuselage, and a plurality of engines. At least one engine can be mounted to each of the opposed wings and at least a portion of each opposed wing including at least one of the plurality of engines can rotate relative to the fuselage around a rotation axis that is non-perpendicular and transverse to a longitudinal axis of the fuselage. Rotating portions of the wings including at least one of the plurality of engines in the described manner can provide a stable and smooth transition between vertical and forward flight.