16 4.5" AA guns (8x2)
44 2pdr AA (5x8,1x4)
60 aircraft 

This class was a further development of the Illustrious class with a flight deck of 760ft effective length, 50ft above the deep load waterline. The catapult could launch 16.000lb at 66kts or 20.000lb at 56kts, and both the forward lift which measured 45ft x 33ft and the 45ft x 22ft after one could take 20.000lb. The upper hangar measured 458ft x 62ft x 14ft and the lower hangar, which was aft, 208ft x 62ft x 14 ft. The clear height of only 14ft prevented the powerful Vought Corsair single-seat fighter from being accommodated. Petrol stowage was 94.650gal, which was low for the 81 aircraft that eventually could be carried with a deck park. The armour belt was not taken above the lower hangar deck, and for much of its length only to the main deck, there being no upper deck. The 3in flight deck was retained with 2½in-1½in on the lower hangar deck over the machinery spaces, while the magazines had separate 3in-2in crowns. Underwater protection resembled that of the Illustrious-class. It was just possible to accommodate the 4-shaft machinery, there being four engine and four boiler rooms, and the smoke ducts from the two port boiler rooms were taken across the ship higher up than in previous designs.

Modifications;
The light AA guns were increased by 8-2pdr (2x4), 4 single 40mm Bofors and 51 20mm Oerlikons in Implacable and by 10 single 40mm Bofors and 40 20mm Oerlikons in Indefatigable.