Flight Lt. Wales (a.k.a. Prince William or the Duke of Cambridge). Arthur Edwards/Getty Images hide caption toggle caption Arthur Edwards/Getty Images The Two-Way Prince William Musters Out: He's Leaving The Military September 12, 2013 The Duke of Cambridge, a new father and second in line to the throne, is leaving after seven years in the RAF. "Flight Lt. Wales" has been a search-and-rescue helicopter pilot. He'll now focus on his royal duties and charity work.