HMS Indomitable (pennant number 92) was a modified Illustrious-class aircraft carrier of the Royal Navy. The Illustrious class was developed in the 1937 Naval Programme. Originally planned to be the fourth of the class, she was redesigned to enable her to operate more aircraft, 48 instead of 36. A second hangar was added above the original, raising the flight deck by 14 feet (4.3 m), although the hangar side armour had to be reduced to compensate. The lower hangar was made shorter than the upper hangar due to the need for extra workshops and accommodation to support the added aircraft.^[​1]