From:
http://www.rafmuseum.org.uk/mileston...tary/1939.html
23 September
The Royal Air Force's first dedicated photographic reconnaissance unit, the Heston Flight, forms at Heston within No.11 Group, RAF Fighter Command. The commander of the flight, Wing Commander Sidney Cotton, had conducted a series of clandestine photographic sorties over Germany on behalf of the Secret Intelligence Service (SIS) as a civilian in the late 1930s. The Heston Flight is renamed No.2 Camouflage Unit on 1 November in an effort to disguise its activities.
26 September
The first Luftwaffe aircraft is shot down during operations against the United Kingdom. A Dornier Do18D flying boat of 2/Küstenfliegergruppe 506 is shot down by a Blackburn Skua of No.803 Squadron, Fleet Air Arm, operating from the aircraft carrier HMS Ark Royal, north of the Great Fisher Bank. The crew of the Do18 are rescued by the destroyer HMS Somali and the aircraft, which was still afloat, is sunk by gunfire.
27 September
By this date, the Royal Air Force (RAF) has dropped 18,000,000 leaflets over Germany.
28 September
Poland surrenders the Germany.
8 October
A Royal Air Force Lockheed Hudson of No.224 Squadron, operating out of RAF Leuchars, shoots down a German Dornier Do18 flying boat of 2/Küstenfliegergruppe 506 25km. This is the first victory recorded of an American-built aircraft in the Second World War and is the first German aircraft to be destroyed by a Royal Air Force aircraft operating from Britain.
10 October
An Empire air training scheme, operating in Canada, New Zealand and Australia, is announced.
16 October
British warships at Rosyth in the Firth of Forth come under attack from Junkers Ju88 of Kampfgeschwader 30 flying from Westerland. Three of the German raiders are brought down, and are the first aircraft destroyed over British territory in the Second World War. The first German aircraft to be shot down, is intercepted by Supermarine Spitfires and comes down in the Firth of Forth near Crail. The pilot, Hauptmann Helmuth Pohle survives and became a Prisoner of War. The successful pilots of No.602 (City of Glasgow) Squadron, Auxiliary Air Force, are Flight Lieutenant G. Pinkerton and Flying Officer A. McKellar.
17 October
Two Luftwaffe air raids take place on warships at Scapa Flow and the first enemy bombs to explode on British soil land on the Island of Hoy in the Orkneys.
28 October
Supermarine Spitfires of No.602 (County of Glasgow) and No.603 (County of Edinburgh) Squadrons bring down a Heinkel He111 of Stab/Kampfgeschwader 26 near Haddington in Lothian. This is the first enemy aircraft to be brought down on mainland Britain during the Second World War.
30 October
Operational service trials of Very High Frequency Radio Telephone are held at Duxford.
30 October
A Hawker Hurricane, piloted by Pilot Officer P.W. Mould of No.1 Squadron, based at Vassincourt in France, shoots down a Dornier Do17 reconnaissance aircraft of 2 (Fernaufklärungs)/Aufklarungsgruppe 123. This is Royal Air Force's first air combat victory over the Continent during the Second World War.
November
The Women's Auxiliary Air Force has recruited 8,800 and has raised its upper age limit to 50 years, for women with experience in radar plotting of aircraft.
1 November The first Chain Home Low radar station becomes operational in Fifeness.
13 November
The first German bombs fall on British soil. The bombs are dropped on the Shetland Islands, with no casualties, except an uninhabited house.
18 November
The first German magnetic anti-ship mines are dropped in British coastal waters.
22 November
The first successful photographic reconnaissance sortie is made by a PR Supermarine Spitfire. Flight Lieutenant M.V. 'Shorty' Longbottom of the Special Survey Flight, a detachment of No.2 Camouflage Unit, flies Spitfire I Type A N3071 on a sortie from Coulommiers to photograph the Eupen - Elsenborn region of northern Luxemburg.
28 November
Six Bristol Blenheim IFs of No.25 Squadron, RAF Fighter Command, and six Blenheim IFs of No.601 Squadron, RAF Fighter Command make a low-level attack on the German seaplane base at Borkum, causing little damage. All the aircraft return safely.
30 November
Soviet Forces invade Finland and fighting continues until an armistice comes into force on 12 March 1940. Despite overwhelming numerical and technical superiority a combination of poor training and tactics sees the Red Air Force lose 280 aircraft in air-to-air combat and 314 to ground defences. Finnish losses total 62 aircraft destroyed in combat and 69 aircraft written off.
3 December
German warships at Heligoland are bombed by 24 Royal Air Force Vickers Wellingtons. A bomb from one of the aircraft hangs up briefly, before dropping on a German AA battery on shore. This is believed to be the first British bomb to strike German soil.
14 December
Six Vickers Wellingtons of No.99 Squadron, RAF Bomber Command, are lost from an attacking force of twelve during an attempted raid on the German Navy cruisers Nurnberg and Leipzig, which have been damaged in a naval action in the North Sea. The Wellingtons are intercepted by Luftwaffe Bf109 fighters, which shoot five down into the sea and the sixth crash lands near Newmarket.
18 December
A third repeat air attack on German shipping off Wilhelmshaven and the Schillig Roads is badly mauled. 12 out of 24 Wellingtons are shot down and others are badly damaged. This ends the British belief that bombers operating in daylight can successfully defend themselves by close formation flying.
21 December
The first 'Gift' squadron is announced, when Nizam of Hyderabad makes a donation to the Royal Air Force. No.152 Squadron is subsequently renamed No.152 (Hyderabad) Squadron.
26 December
The first Royal Australian Air Force squadron, No.10 Squadron RAAF, arrives in Britain for service alongside the Royal Air Force.