Mk I Hawker Hurricane fighters of the Air Component of the British Expeditionary Force go up against Messerschmitt Bf 109 'Emils' of the Luftwaffe along the Franco-German border in March 1940. The so-called Phoney War involved constant aerial skirmishes until the Battle of France kicked off in May. At this time the RAF was using distinctive black-white-metal underside colour schemes on its fighters.