NEW YORK — In July 1944, Orson Welles wrapped up one of his wartime radio broadcasts with a brief, emotional reading of one of the country’s favorite authors, John Steinbeck. The piece was titled “With Your Wings,” an inspirational story about a black pilot that Steinbeck wrote for Welles’ program, and it seemed to disappear almost as soon as it was aired. There are no records of “With Your Wings” appearing in book or magazine form. Even some Steinbeck experts, including scholar Susan Shillinglaw and antiquarian James Dourgarian, know little about it.