The lift produced by a wing is directly related to the speed of the air over the wing. Since the airflow speed experienced by a swept wing is lower than what the actual aircraft speed is, this becomes a problem during slow-flight phases, such as takeoff and landing. There have been various ways of addressing the problem, including the variable-incidence wing design on the Vought F-8 Crusader,[24] and swing wings on aircraft such as the F-14, F-111, and the Panavia Tornado.[25][26]