The Maritime Self-Defense Force is upgrading its Izumo and Kaga destroyers into de facto aircraft carriers, equipping them to operate the F-35B stealth fighter, which features short takeoff and vertical landing capabilities.
Performance tests conducted in October and November last year, with cooperation from the U.S. Navy and Marine Corps, confirmed that the upgraded Kaga can accommodate the F-35B without issue.
Also, the original Kaga being an aircraft carrier was because the US was more-concerned about Japan having a ton of battleships that might be a threat to the US and negotiated battleship limits in the Washington Naval Treaty, so it was converted into an aircraft carrier…which turned out when World War II came around, to be a lot more potent than battleships were, so there was an even earlier reversal in position.