Jose Luis Magana/AP Photo

Making its way to South Africa, Air Force One transported a rare assembly of travel companions last night, including a current president, a former president and three first ladies, one of whom may be a possible future president.

President Obama and First Lady Michelle Obama were joined by former President George W. Bush, former First Lady Laura Bush, and former First Lady Hillary Clinton for the long flight to Johannesburg to attend a memorial service for the late South African leader Nelson Mandela.

The high-powered travelers and former political rivals caught up and shared memories about the revered statesman and anti-apartheid leader as they sat together around a conference room on the customized 747, with the current president joining them between meetings and other work.

"It's a unique experience, obviously," Deputy National Security Advisor for Strategic Communications Ben Rhodes told reporters aboard the flight. "I think they all are remembering their different interactions with Nelson Mandela and his family, because again, he is a leader that intersected with so many different American political leaders of both parties over the years, and so each of them has their own experience with Mandela."

The rare get-together made for some unique sleeping arrangements on a plane that doesn't often cater to so many presidents and first ladies. During the flight, the Obamas are staying in the presidential cabin in the nose of the plane, the Bushes in the medical office just behind, and Clinton in the senior staff cabin behind that.

"It's a very, I think, enjoyable experience, certainly for the president and first lady," Press Secretary Jay Carney said. "And they're both grateful to be able to have the former president and first lady, former secretary of state on board."

Presidents Obama and Bush will be joined upon arrival by former Presidents Bill Clinton and Jimmy Carter, who are making their own way to South Africa for the memorial service. Former President George H.W. Bush is the only living U.S. president unable to attend because he can no longer travel such long distances.

It's been 14 years since this many U.S. presidents attended an event together on foreign soil. In February 1999, President Bill Clinton and former presidents Bush, Carter and Ford attended the state funeral of King Hussein in Amman. Similarly, all four traveled to Jordan together aboard Air Force One.

President Obama is slated to speak today at the memorial service for Mandela at the stadium in Johannesburg.