 Boothroyd's initial aerial success with 20 Squadron came on 2 July 1918, when he destroyed a Fokker D.VII near Geluwe.On 11 August, he destroyed a kite balloon south of Heule.Then, on 20 September, he began a streak of ten victories that took him through double wins on 23 and 30 October; for this latter pair of double triumphs, he was piloted by fellow ace Capt.Horace Percy Lale.