The FAA decided to accept a delay in delivery to get Martlets fitted out with the Grumman-designed and patented "Sto-Wing" folding wing system first fitted onto U.S. Navy F4F-4 Wildcats, which were vitally important if the Martlet was to be used from the first 3 Illustrious class carriers which had elevators that were too narrow to accommodate non-folding wing aircraft.