Beginning approximately one hour after Earhart's last recorded message, the USCGC Itasca took a search north and west of Howland Island. The United States Navy soon joined the search and over a period of about three days sent available resources to the search area in the vicinity of Howland Island.
The official search efforts lasted until July 19, 1937. At $4 million, the air and sea search by the Navy and Coast Guard was the most costly and intensive in U.S. history. But search and rescue techniques during the era were introductory and some of the search was based on erroneous assumptions.
Despite an unprecedented search by the United States Navy and Coast Guard no physical evidence of Earhart, Noonan or the Electra 10E was found.
In late July 1937, Putnam chartered two small boats and while he remained in the United States, directed a search of the Phoenix Islands, Christmas Island, Fanning Island, the Gilbert Islands and the Marshall Islands, but no trace of the Electra or its occupants was found.
Back in the United States, Putnam acted to become the trustee of Earhart's estate so that he could pay for the searches and related bills. In a court in Los Angeles, Putnam requested to have the "declared death in absentia" seven-year waiting period waived so that he could manage Earhart's finances. As a result, Earhart was declared legally dead on January 5, 1939.