To train for the role of Lieutenant Burch, Walter Matthau underwent Naval technique training and flight plotting skills aboard the U.S.S. Ticonderoga. In real life, Matthau served in World War II as a radio operator attached to a bomb squadron in Europe and Germany. Matthau won six battle stars.
As a young G.I. in World War II, Walter Matthau served under the command of James Stewart. Fifty years later, Matthau reflected on this experience at the American Film Institute when Jimmy Stewart was honored with the AFI Lifetime Achievement Award.