Boris Johnson and Canadian Prime Minister Justin Trudeau compared the size of their official planes when they held talks in Bavaria today.
The pair met on the margins of the G7 Summit in Germany - and began by discussing their aircraft.
Mr Johnson told his Canadian counterpart he spotted “Canada Force One” on the Tarmac at Munich Airport when he touched down this morning having flown eight hours from the Commonwealth Heads of Government meeting in Rwandan capital, Kigali.
“Can Force One”, as the plane is known, is an Airbus A310 categorised as a CC-150 Polaris.
Mr Trudeau joked that Mr Johnson’s Airbus A321 plane was bigger - to which the British PM insisted that his jet is “very modest”.
The Tory leader has been forced to use the smaller of his two jets because Prince Charles had first call on the Airbus A330 RAF Voyager to fly to Rwanda, because of protocol.
The Voyager was converted from a troop carrier and air-to-air refuelling tanker to be used by the UK PM and aides on foreign trips.
The revamp cost taxpayers £10million - and when Mr Johnson entered No10 he demanded a £900,000 paint job to switch the aircraft from military grey to patriotic red, white and blue.
Mr Johnson also met French President Emmanuel Macron as the crucial gathering of world leaders kicked off today.
The PM and Mr Macron put their arms around each other’s shoulders as they slapped each other on the back.
The French premier had removed his jacket as the summit was bathed in summer sunshine and temperatures reached 25C.
Mr Johnson asked Mr Macron, who also suffered an election setback last week, how he was.
The President replied: “I’m fine.”
The summit is expected to be dominated by the West’s response to Vladimir Putin 's brutal invasion of Ukraine.
Mr Johnson admitted he was worried about allies’ support for Ukraine waning as he prepared for crunch talks at the G7.
Warning that "realistically there is going to be fatigue in populations and politicians", he added: "I think the pressure is there and the anxiety is there, we've got to be honest about that.
"But the most incredible thing about the way the West has responded to the invasion of Ukraine by Putin has been the unity - NATO has been solid, the G7 has been solid and we continue to be solid.
"But in order to protect that unity, in order to make it work, we've got to have really, really honest discussions about the implications of what's going on, the pressures that individual friends and partners are feeling, that populations are feeling - whether it's on the costs of their energy or food or whatever."
Asked whether France and Germany are doing enough over Ukraine, the PM praised Berlin’s efforts without mentioning France.
"Just look at what the Germans alone have done," he said.
"I never believed in my lifetime that I would see a German Chancellor stepping up in the way that Olaf Scholz has and sending weaponry to help the Ukrainians to to protect themselves.
"He's made huge, huge strides. We have 4% of our gas comes from Russia, in Germany, it's 40%."
Meanwhile, Britain will ban imports of Russian gold in the latest stage of the effort to cripple Russia's economy over the war in Ukraine.
In a coordinated announcement, the UK, US, Canada and Japan unveiled plans to block shipments.
Gold exports were worth £12.6billion to Moscow last year.
