Question:  David John Shannon was selected to join the newly formed No. 617 Squadron by the most highly decorated serviceman in the country who completed over how many operations at the age of 26?
Sentence (from "William George Barker"): William George "Billy" Barker, (3 November 1894 – 12 March 1930) was a Canadian First World War fighter ace and Victoria Cross recipient.
Relevant evidence: No