Western Front: Significant numbers of SE5, Sopwith Triplane, Bristol Fighter and Spad S 13 enable Allies to regain air superiority.
USA: In June Major Raynal C Bolling Mission leaves USA for two-month tour of Allied aircraft manufacturing in Europe and remit to conclude licence production agreements.
Adriatic: In June No 6 Wing Royal Navy Air Service begins anti-U-boat patrols from Otranto.
Britain: BEF has taken 76,067 PoWs to date.
Germany: During June Rupprecht transfers 10 divisions from Lens-Lille sector to Flanders.
Aisne: Up to 2,000 men of French 23rd and 133rd Infantry Regiments (43rd Division) mutiny until June 2 at Ville-en-Tardenois and Chambrecy (southwest of Reims), display red flag. German 4-coy local dawn attack preluded by 3-minutes mortar shelling and indirect MG fire behind French first line.
Britain: During June Convoys being regularly run, 113 destroyers available for escort in Home Waters, 37 in Mediterranean, average of 55 U-boats at sea per day.
Mediterranean: 18 German and 3-4 Austrian U-boats on operations (until June 15).