Victoria Cross Awarded for most conspicuous bravery or some daring or pre-eminent act of valour or self-sacrifice or extreme devotion to duty in the presence of the enemy. 

George Cross For an act of the greatest heroism or of the most conspicuous courage in circumstances of extreme danger. Awarded primarily to civilians.

Distinguished Service Order For military officers only; rewarding individual instances of meritorious or distinguished service in war. Normally given for service under fire or under conditions equivalent to service in actual combat with the enemy. 

Distinguished Flying Cross Awarded to officers and Warrant Officers for an act or acts of valour, courage, or devotion to duty performed whilst flying in active operations against the enemy. 

Air Force Cross Awarded to officers and Warrant Officers for an act or acts of valour, courage, or devotion to duty performed whilst flying, but not while in active operations against the enemy. 

Conspicuous Gallantry Medal (RAF) Awarded to WO's, NCOs, and non-commissioned members of the Air Forces and Military for acts of conspicuous gallantry whilst flying in active operations against the enemy

George Medal Awarded only for acts of great bravery and was intended primarily for civilians. 

Distinguished Flying Medal Awarded to non-commissioned officers and men for an act or acts of valour, courage or devotion to duty performed whilst flying in active operations against the enemy. 

Air Force Medal Awarded to non-commissioned officers and men for an act or acts of valour, courage or devotion to duty performed whilst flying, though not in active operations against the enemy. 

1939-45 Star Awarded for six months service on active operations for the Army and Navy and two months for active air-crew service.

Air Crew Europe Star Awarded for two months of operational flying from the UK over Europe between 03 September 1939 and 05 June 1944.

War Medal (1939-45) Awarded to all full-time personnel of the Armed Forces and Merchant Marines for serving for 28 days between 03 September 1939 and 02 September 1945.

Canadian Volunter Service Medal Granted to persons of any rank in the Naval, Military or Air Forces of Canada who have voluntarily served on Acitve Service.

Defence Medal Usually awarded to Canadians for six months service in Britain between 03 September 1939 and 08 May 1945, the exact terms were: Service in the forces in non-operational areas subjected to air attack or closely threatened, providing such service lasted for three or more years. More info at Veterans Affairs site.