What is Walter Bowman's importance in the novel, Unintended Consequences?

Walter Bowman, Henry's father, joined the Army Air Corps during World War II and was stationed in Florida as a trainer of pilots. He met a mechanic there and together, they built an amazing plane against regulations, but known by everyone on the base. At war's end, the commanding officer told Walter to fly the plane home, and it was passed on to son Henry when he died. While his first love was flying, Walter also was a bit of a gun enthusiast and strongly encouraged Henry's abiding interest in them as well. His early death from cancer left the family wealthy but Henry without a critical void in his life.