Sentence:  He had no prearranged signals for explaining the presence of the two Americans, but when the planes returned to check his messages, he <WSD>wigwagged</WSD>: "No Japanese. No signs," and then led Krickel and his daughter to where they could be clearly seen. The lead plane dipped its wings alterately and flew back toward Dutch Harbor. 
Meaning of the word marked with <WSD> tags:  To send a signal by waving a flag to and fro.