The Polish Air Forces (Polskie Siły Powietrzne) was a name of Polish Air Forces formed in France and the United Kingdom during World War II. The core of the Polish air units fighting alongside the allies were experienced veterans of Invasion of Poland of 1939 and they contributed to Allied victory in the Battle of Britain and most World War II air operations.
Władysław Eugeniusz Sikorski during World War II became Prime Minister of the Polish Government in Exile, Commander-in-Chief of the Polish Armed Forces, and a vigorous advocate of the Polish cause in the diplomatic sphere. He supported the reestablishment of diplomatic relations between Poland and the Soviet Union, which had been severed after the Soviet pact with Germany and the 1939 invasion of Poland —however, Soviet dictator Joseph Stalin broke off Soviet-Polish diplomatic relations in April 1943 following Sikorski's request that the International Red Cross investigate the Katyń Forest massacre.
In World War II, the Battle of France, also known as the Fall of France, was the German invasion of France and the Low Countries, executed on 10 May 1940, which ended the Phoney War. The battle consisted of two main operations. In the first, Fall Gelb (Case Yellow), German armoured units pushed through the Ardennes, to cut off and surround the Allied units that had advanced into Belgium. The British Expeditionary Force (BEF) and many French soldiers were evacuated from Dunkirk in Operation Dynamo. In the second operation, Fall Rot (Case Red), executed from 5 June, German forces outflanked the Maginot Line to attack the greater French territory. Italy declared war on France on 10 June. The French government fled to the city of Bordeaux, and France's main city of Paris was occupied by the German Wehrmacht on 14 June. On the 17 June, Pétain publicly announced France would ask for an armistice. On 22 June, an armistice was signed between France and Germany, going into effect on 25 June. For the Axis Powers, the campaign was a spectacular victory.