A special service has been held to remember the thousands of Canadian aircrew killed on bombing raids over Europe in the Second World War.
Veterans and present day air force personnel attended the ceremony at Allerton Castle near Knaresborough.
Chris Kiddey talks to former airman Douglas Petty, Jean Lumsden who worked at the headquarters and Tressa Home from the Canadian High Commission in his report.
A unique moment in history will take place today when three Lancaster Bombers will be together in Lincolnshire.
The RAF's Lancaster "Thumper" and the Canadian Lancaster "Vera" will overfly Britain's only other running Lancaster "Just Jane" as it taxis on the runway at the Lincolnshire Aviation Heritage Centre in East Kirkby. Some five thousand spectators are expected to be at the airfield to witness the first opportunity to see three Lancaster Bombers and hear 12 Merlin engines working together since the 1960s.
Gates open at 10am and the flypast is scheduled for 4.20pm.
The two remaining airworthy Lancaster bombers will fly over North Yorkshire's Allerton Castle, the wartime headquarters of No 6 Group, Royal Canadian Air Force today to commemorate the shared experience of UK and Canadian pilots
Although 7,377 Lancaster aircraft were produced between 1941 and 1946, only two remain airworthy. One, a Mk 1 nicknamed 'Thumper' is maintained by the RAF's Battle of Britain Memorial Flight , and the other, named Vera for its identification markings V-RA, by the Canadian Warplane Heritage Museum.
The historic fly past at Allerton Castle will be accompanied by a ceremony attended by Royal Air Force personnel and veterans who served within Canadian crews.
The world's two remaining Lancaster bombers that can fly have taken to the skies together over Lincolnshire for the first time this lunchtime.
A Lancaster from the Battle of Britain Memorial Flight and another known as Vera, which is usually based in Canada, took off at RAF Coningsby. They are preparing to take part in a number of airshows together in the next six weeks.
Last week thousands of people gathered at RAF Coningsby in Lincolnshire hoping to witness a once in a lifetime sight - the last two operational Lancaster Bombers in the world, flying side by side.
Sadly, it was not to be. Bad weather meant that the historic flight had to be postponed
But the crowds did get to see a visiting Canadian Lancaster known as Vera land for a salute to former bomber command veterans.
Despite the disappointment plane spotters are still heading to the base in the hope of catching a glimpse of the bomber.
Al Mickelloff, from the Canadian Warplane Heritage Museum, said he had been disappointed - but it was still a historic occasion:
The rain ruined the airborne reunion of the Lancaster Bombers, but thousands of people still braved the pouring rain to see the arrival of the Canadian Bomber, V-Vera at the end of its three and a half thousand mile journey.
Over the next few weeks it'll take part in a series of events with the Lancaster from the Battle of Britain Memorial Flight.
David Wood reports:
The weather has ruined plans for a historic fly-past of Lancaster planes in Lincolnshire.
The Battle of Britain Memorial Flight will now not take off - but it will meet the Canadian Avro plane on the ground at RAF Coninsgby.
There will still be a flypast of the Canadian plane and the Red Arrows.
RAF Coningsby is gearing up for special visitors today.
A Canadian Lancaster will join the Battle of Britain Memorial Flight over Lincolnshire today.
The Canadian plane will make its way over Scunthorpe just before 1pm, over Hilbadstow at 1pm, where it will be joined by the Battle of Britain Memorial Flight.
They will then fly towards Scampton where they'll be joined by the Red Arrows.
At 1.15pm all will fly over Lincoln Cathedral,
At 1.24pm the Red Arrows will fly over Newark, while the 2 Lancasters will fly over Cranwell.
At 1.28pm the Reds rejoin the Lancaster and BBMF over Tattershall, to fly together over Coningsby.