On May 4, 1942, the Battle of the Coral Sea began. From the article:
"Battle of Coral Sea
This four-day World War II skirmish in May 1942 marked the first air-sea battle in history. The Japanese were seeking to control the Coral Sea with an invasion of Port Moresby in southeast New Guinea, but their plans were intercepted by Allied forces. When the Japanese landed in the area, they came under attack from the aircraft carrier planes of the American task force commanded by Rear Admiral Frank J. Fletcher. Although both sides suffered damages to their carriers, the battle left the Japanese without enough planes to cover the ground attack of Port Moresby, resulting in a strategic Allied victory.
The first air-sea battle in history and an engagement in which the lead role was played by aircraft launched from ships at sea, this battle resulted from Japanese efforts to make an amphibious landing at Port Moresby in southeast New Guinea. Unknown to the Japanese, Allied codebreakers had learned enough about enemy communications to discern Japanese plans in time for Allied fleets to assemble in the Coral Sea.
Rear Admiral Frank J. Fletcher commanded American task forces, including two large aircraft carriers and other ships, and a British-led cruiser force mounted surface opposition. The Japanese used many more ships but divided them into a number of widely separated groups, one of which contained a light carrier. The Japanese covering force (led by Vice Admiral Takagi Takao) also contained two large carriers.
There were a number of missed opportunities as carrier airmen learned their trade. Air strikes from both sides either missed their targets or found them only after using up their ordnance. Americans connected first, sinking the light carrier Shoho. When the main forces traded air strikes, the Americans lost the carrier Lexington (Yorktown was also damaged), and the Japanese suffered damage to the carrier Shokaku.
Without air cover, however, the Japanese invasion force turned back, leaving the strategic victory to the Allies. The results had an important impact upon the Battle of Midway a month later, reducing Japanese forces available at that key battle."