The Prince of Wales is flying to Washington for a two-day official visit that will see the royal call on US President Barack Obama.
Charles will meet the president in his Oval Office at the White House on Wednesday for talks on a range of subjects ahead of Mr Obama's state visit to the UK later this month.
Charles will travel to America in the private plane of US financier Joe Allbritton in a bid to save on travel costs. It is thought to be the first time the heir to the throne has used an aircraft paid for by a private individual for an official visit.
The move is likely to save the British taxpayer tens of thousands of pounds. But Charles may face criticism from the green lobby as the aircraft will make a number of trips without passengers.
Mr Allbritton, who is a corporate supporter of the Prince's charities and a personal friend, was invited to the recent wedding of Prince William and his new wife Kate, now the Duke and Duchess of Cambridge.
Outlining the official trip, a Clarence House spokesman said: "The Government has asked the Prince of Wales to pay a visit to the United States, needless to say our friendship with the United States is one of the most important - given the special relationship. And it's crucial that we sustain this relationship with regular high-profile visits that focus on a wide range of issues that reflect the full depth and breadth of our shared interests."
The spokesman said the visit has three main themes - environmental sustainability, co-operation between UK and US forces with particular emphasis on the welfare and support of injured service personnel, and education.
Later Charles will visit America's Supreme Court in Washington to celebrate the Marshall Scholarships. The British project, established by an Act of Parliament in 1953, funds Americans to study at UK universities in recognition of the post-war European recovery programme, known as the Marshall Plan.
Charles will go on to visit a "common good" city farm in a deprived area of Washington, where a softball field has been turned over to growing produce by local volunteers.
In the evening, the royal will attend a reception to celebrate the work of a British body and its US counterpart which both organise morale boosting events for troops. The Prince will also meet injured US servicemen and women.