Royal Navy | Royal Air Force | Royal Dutch Shell | Royal Society | Royal Albert Hall | Royal Shakespeare Company | Royal Opera House | Royal Victorian Order | Royal Engineers | Royal Australian Navy | Royal National Theatre | Royal Canadian Navy | Royal Canadian Air Force | Royal Court Theatre | Royal Marines | aircraft | Royal Commission | Royal Academy of Music | Anne, Princess Royal | Royal Philharmonic Orchestra | Theatre Royal, Drury Lane | Royal Flying Corps | Royal Canadian Mounted Police | Royal Australian Air Force | Royal Artillery | Royal Festival Hall | Royal College of Art | Royal Botanic Gardens, Kew | British Royal Family | Royal College of Music |
He then joined 25 Squadron in July 1917, flying the Royal Aircraft Factory FE.2d and then the Airco DH.4 bomber, claiming with his gunner David Luther Burgess some 7 aircraft shot down during July and August.
A combat with No. 57 Squadron RFC Royal Aircraft Factory FE.2d's over Neuville on 2 April 1917 resulted in Festner claiming a FE-2d(Lt. H.P. Sworder KIA & 2/Lt. A.H. Margoliouth,POW).
He and his observer were credited with an aerial victory on 17 March 1917, when they shot down a Royal Aircraft Factory FE.2d from No. 20 Squadron RFC over Lomme.