Post No 2 wrote:
Flying at high altitudes we could look down and see the literally thousands of small cumulus clouds dotting the vast ocean from horizon to horizon - each cloud casting a shadow on the water. With their Lockheed flying over the Pacific among those low level clouds where the base of the fair weather CU would be around 1000 ft and tops around 3000 ft, any one of those shadows could be an atoll. It was an illusion of course.
Post 49 quotes from the first draft of Amelia Earhart's memoirs where she wrote:
"There is no doubt that the last hour of any flight is the hardest. If there are any clouds about to make shadows, one is likely to see much imaginary land."
While one can appreciate the differing points of view expressed by Pprune contributors and varying scenarios put up for consideration, this contributor leans towards a simpler explanation.. That is, after 20 hours of flying towards Howland island, in the end they were fooled by the shadows under the low altitude clouds and were lost and forced to ditch.