A method of configuring a wing tip device (7) on an aircraft (1), including: undertaking ground-based operations at an airport with the wing tip device (7) in a ground configuration, in which the span of the aircraft is within an airport compatibility limit, moving the wing tip device (7) to a take-off configuration in which the wing tip device (7) is moved away from the ground configuration such that the span of the aircraft is increased and such that the wing tip device (7) has a first lift coefficient; taking-off with the wing tip device (7) in the take-off configuration; moving the wing tip device from the take-off configuration to a flight configuration, in which the wing tip device has a second lift coefficient, the second lift coefficient being lower than the first lift coefficient. The lift coefficient may be changed by adjusting the sweep of the wing tip device (7).