In 1938, the German military machine was far more advanced than ours and the French. Their airforce had turned their 'civilian passenger aircraft' (Heinkel He 111 & Dornier Do 17) into bombers, that had been the intention all along. We still had biplane fighters with front-line units whereas the Germans had the monoplane Messerschmitt Bf 109, and the emerging Bf 110. Aerially, we would have been slaughtered had war broken out in 1938.
Chamberlain, unwittingly, bought us those 12 months, and by the time of the Dunkirk evacuation in late-May/early-June 1940, Fighter Command had the Spitfires and Hurricanes in sufficient quantities with front-line units, together with the most modern defensive aerial set-up in the world at that time, upon which the Luftwaffe were broken in the following months of the Battle of Britain.
But 12 months earlier...
Apologies for digressing, but Chamberlain should be seen in the above light, even though he was not to know it at the time.