I understand that in certain bombing runs the planes could launch from an aircraft carrier and fly over the targets to an allied country (like during the Doolittle Raids). But in a scenario such as Pearl Harbor, with no allies of Japan around, where did these planes land?
The attack on Pearl Harbor was launched from six Japanese aircraft carriers steaming to the north and northeast of Pearl Harbor. Japanese aircraft were launched in two "waves" of planes, flying through the valleys and around the cost of Oahu to converge on targets near Pearl Harbor. Although the ships of the US Pacific Fleet were the main target, Japanese aircraft also attacked army airfields and bases elsewhere on the island.
As to where the planes landed: they landed back on the carriers that launched them, except for the 29 that were lost due to American defensive measures.