 When the wing is swept back, its thickness-to-chord ratio decreases, which allows the aircraft to satisfy the Mach 2.4 top speed required by the U.S. Navy.The body of the aircraft contributes significantly to overall lift and so the Tomcat possesses a lower wing loading than its wing area would suggest.When carrying four Phoenix missiles or other heavy stores between the engines this advantage is lost and maneuverability is reduced in those configurations.