The 27,500-ton USN had a hangar that was designed to handle a mix of 72 prewar USN aircraft. but carried up to 104 late-war aircraft using both the hangar and a permanent deck park. The experience of World War II caused the USN to change their design policy in favor of armored flight decks on much larger ships: "The main armor carried on is the heavy armored flight deck. This was to prove a significant factor in the catastrophic fire and explosions that occurred on "Enterprise"s flight deck in 1969. The US Navy learned its lesson the hard way during World War II when all its carriers had only armored hangar decks. All attack carriers built since the have had armored flight decks."