I think this might be the book you're talking about. The plane was going from Hawaii to New Zealand when the Japs attacked Pearl Harbor. Pan Am directed it not to return to Hawaii for fear of being attacked. They were told to make their way back to New York "the best way they could" which entailed going the long way around the globe to avoid the Pacific. The book is called "the long way home" by Ed Dover. Ed was a Pan Am crew member at the time who was friends with the captain involved. He wrote the book from first hand accounts. Not sure if the book is still in print, but I was able to get an autographed copy from the author thru Amazon.com a few years back. It's a short book and very interesting.