Once the Pearl Harbor operation was completed, there was a lack of strategic long term planning to identify concrete goals for the First Air Fleet. Nagumo and his naval force were national heroes, and as 1942 dawned, they were given tasks that both sapped their strength and did not acknowledge that the US carriers were still afloat.
On the return voyage from Hawaii, two carriers were detached, one to support the landings on Wake Island, and another to support the landings in Malaysia. Nagumo, with his four remaining carriers, was given orders to enter the Indian Ocean and strike Allied installations at Tricomlee on Madagascar.
The obvious deviation from the primary target of the US carriers was noted by many aboard the First Air Fleet, including Mitsuo Fuchida, who had led the air armada over Pearl Harbor. He would later write that the Indian Ocean operations were a wasted mission for the best and most highly trained weapons in the Imperial Japanese Navy.
Nevertheless, the First Air Fleet was successful in its attacks, wiping out the United Kingdom aircraft on the ground. HMS Hermes and other capital ships were sunk, and on the return voyage to Japan, the First Air Fleet bombed Darwin.
Upon their return to home waters, the First Air Fleet found out that two of their number would not be returning immediately. The Shokaku and and Zuikaku, detached to support attacks, were sent to support a landing on New Guinea, in a small port that was the Allied base of operations on the island. The battle for Port Moresby would be a battle on land, the high command was certain, and naval aircraft would be needed to support it. No one in the Japanese command could guess that the marus would never land their troops. The Battle for the Coral Sea was coming, and it would change the way navies fought forever.