Western Front: Canadian ace Captain Bishop flies dawn raid on German airfield near Cambrai, destroying 3 Albatros fighters that rise to engage; returns to base in bullet-riddled Nieuport figher (Victoria Cross award on August 11).
Flanders: Royal Flying Corps Second Army aircrafts destroy 32 aircraft for loss of 18 (until June 7).
France: New French C-in-C Petain’s CoS Debeney informs Haig that, due to mutinies, French Army can give only minimal support in planned Allied offensive. Haig decides to attack a key sector immediately and so distract Germans from French; Messines offensive already scheduled for June 7 fits the bill.
Eastern Mediterranean: British transport Cameronian (63 men lost) sunk 50 miles off Alexandria.