This is a list of aviation-related events from 1940:

Events

March

• March 16 - Britain suffers its first civilian air-raid casualties of the war after a raid by KG 26 on Scapa Flow
• March 25 - the US government grants permission to the country's aircraft manufacturers to sell advanced combat aircraft to nations fighting the Axis powers.

April

• April 9 - Germany invades Denmark and Norway, making extensive use of paratroops
• April 13 - the Royal Air Force begins deploying sea mines around Germany's coastal waters.
• April 24-28 - aircraft carrier HMS Glorious evacuates the Gloster Gladiators of No. 263 Squadron RAF from Norway

May

• May 10 - Germany invades the Netherlands, Belgium, and Luxembourg. Paratroops again play a key role.
• May 13 - the Sikorsky VS-300 , which made its first flight the previous year, makes its first untethered flight.
• May 15-16 - British bombers make their first attack on German land targets, in the Ruhr Valley

June

• June 4 - BOAC commences a twice-weekly service between England and Portugal, scheduled to connect with Pan Am flights from Lisbon to New York.
• June 8 - after a second expedition to Norway, HMS Glorious is sunk by German battlecruisers (or light battleships) Scharnhorst and Gneisenau.
• June 10 - Italy declares war on Britain and its allies and begins an aerial assault on Malta.

July

• July 1 - the Battle of Britain commences with the German occupation of the Channel Islands.

August

• August 15 - the heaviest fighting of the Battle of Britain occurs, with the loss of 46 British and 76 German aircraft.
• August 25-26 - Britain makes its first air raid on Berlin of the war.
• August 31 - Polish 303 Squadron , the most efficient allied unit of the Battle of Britain, enters action.

September

• September 7 - Hermann Göring orders the Luftwaffe to stop targeting British airfields and attack London itself instead.
• September 7-September 8 - the largest mass air combat in history takes place over Britain, with 1,200 British and German aircraft operating in an area of only 24 x 48 km (15 x 30 miles).
• September 15 - Germany makes its heaviest daylight raid on London
• September 30 - the Battle of Britain is said to be over, with Hitler's planned invasion of Britain ("Operation Seelöwe") postponed indefinitely.

October

• October 8 - No. 71 Squadron RAF , "Eagle Squadron" is formed, comprising American volunteers.
• October 8 - Josef František, the Czech ace (17 victories) - the most efficient allied pilot of the Battle of Britain, died in an aircrash.

November

• November 5 - four RAF squadrons are deployed to Greece to support the country against Italian attacks.
• November 11 - regular ferry flights of US-built warplanes commence across the Atlantic.
• November 11-12 - Fairey Swordfish from HMS Illustrious make a highly successful raid against Regia Marina ships at Taranto, damaging battleship Conte di Cavour beyond repair, and extensively damaging two others, Littorio and Caio Duilio (Battle of Taranto).
• November 14-15 - 437 Luftwaffe aircraft make a massed air raid on Coventry. 380 civilians are killed and some 800 wounded.

December

• December 29-30 - the Luftwaffe makes a devastating attack on London, making extensive use of incendiary weapons.

First flights

• Ikarus Aero 2

January

• January 4 - Fairey Fulmar production aircraft N 1854
• January 13 - Yakovlev Ya-26, prototype of the Yakovlev Yak-1

February

• February 24 - Hawker Typhoon prototype P 5212

March

• March 20 - Armstrong Whitworth Albemarle prototype P 1361

May

• May 29 - Vought XF4U-1

August

• August 28 - Caproni-Campini N.1, thermojet-powered aircraft

September

• September 7 - Blohm & Voss BV 222
• September 14 - Miles M.20

October

• October 12 - Ilyushin TsKB-57, prototype of the Ilyushin Il-2
• October 18 - Airspeed Fleet Shadower
• October 26 - North American NA-73X, prototype of the P-51 Mustang

November

• November 25 - de Havilland Mosquito prototype W 4050
• November 29 - Junkers Ju 288

December

• December 7 - Fairey Barracuda prototype P 1767
• December 18 - Curtiss SB2C Helldiver

Entered service

February

• Blackburn Roc

March

• Fairey Albacore with No. 826 Squadron FAA

May

• Dewoitine D.520 with French squadrons

July

• Fairey Fulmar with No. 806 Squadron FAA
• Westland Whirlwind with No. 263 Squadron RAF

November

• Avro Manchester with No. 207 Squadron RAF
• November 23 - Handley Page Halifax with No. 35 Squadron RAF