A method of manufacturing an aircraft wing, the wing comprising a fixed wing extending from a root, for locating at a junction with an aircraft fuselage, to a tip, and a wing tip device at the tip of the fixed wing, wherein the wing tip device is rotatable relative to the fixed wing between • a flight configuration for use during flight, in which flight configuration the trailing edge of the wing tip device is a continuation of the trailing edge of the fixed wing, the leading edge of the wing tip device is a continuation of the leading edge of the fixed wing, and the upper and the lower surfaces of the wing tip device are continuations of the upper and lower surfaces of the fixed wing, and • a ground configuration for use during ground-based operations, in which ground configuration the wing tip device is rotated relative to the fixed wing such that the span of the wing is reduced, the method comprising the steps of, designing the wing by: a) determining the orientation of an Euler axis of rotation for rotating the wing tip device from the flight configuration to the ground configuration, the Euler axis being angled with respect to all three of a longitudinal direction, a lateral direction and a vertical direction, the longitudinal, lateral and vertical directions all being mutually perpendicular to one another, and then determining the location of a cut plane separating the fixed wing and the wing tip device, the cut plane being orientated normal to the Euler axis and creating an overcut or an undercut with respect to the fixed wing; or b) determining the location and orientation of a cut plane separating the fixed wing and the wing tip device and creating an overcut or an undercut with respect to the fixed wing, and then determining the location of an Euler axis of rotation for rotating the wing tip device from the flight configuration to the ground configuration, the Euler axis being orientated normal to the cut plane and being angled with respect to all three of a longitudinal direction, a lateral direction and a vertical direction, the longitudinal, lateral and vertical directions all being mutually perpendicular to one another, and iteratively repeating step (a) or step (b) until a preferred cut plane is obtained that achieves one or more design criteria; and then manufacturing a wing according to this design. • a flight configuration for use during flight, in which flight configuration the trailing edge of the wing tip device is a continuation of the trailing edge of the fixed wing, the leading edge of the wing tip device is a continuation of the leading edge of the fixed wing, and the upper and the lower surfaces of the wing tip device are continuations of the upper and lower surfaces of the fixed wing, and • a ground configuration for use during ground-based operations, in which ground configuration the wing tip device is rotated relative to the fixed wing such that the span of the wing is reduced, a) determining the orientation of an Euler axis of rotation for rotating the wing tip device from the flight configuration to the ground configuration, the Euler axis being angled with respect to all three of a longitudinal direction, a lateral direction and a vertical direction, the longitudinal, lateral and vertical directions all being mutually perpendicular to one another, and then determining the location of a cut plane separating the fixed wing and the wing tip device, the cut plane being orientated normal to the Euler axis and creating an overcut or an undercut with respect to the fixed wing; or b) determining the location and orientation of a cut plane separating the fixed wing and the wing tip device and creating an overcut or an undercut with respect to the fixed wing, and then determining the location of an Euler axis of rotation for rotating the wing tip device from the flight configuration to the ground configuration, the Euler axis being orientated normal to the cut plane and being angled with respect to all three of a longitudinal direction, a lateral direction and a vertical direction, the longitudinal, lateral and vertical directions all being mutually perpendicular to one another,