ABOARD AIR FORCE ONE (AP) — As Air Force One made its way from Washington to Johannesburg Monday, a president, a former president and a possible future president were all traveling aboard.

The high-powered traveling partners came together for a transcontinental trip to South Africa for a memorial service honoring Nelson Mandela, the former South African leader who died last week at the age of 95. The unusual manifest required some creative seating arrangements on the presidential plane.

Obama and Michelle Obama occupied the president's stateroom at the front of the plane. Former President George W. Bush and wife Laura were settled nearby in the plane's medical suite, which can function as an operating room. And former Secretary of State Hillary Clinton — a potential candidate for president in 2016 — was given a spot in a cabin normally occupied by senior staff.

The plane's spacious conference room served as a gathering spot for the former president and three first ladies, with the current commander-in-chief popping in between in-flight meetings and calls. And there was no shortage of time for catching up. The flight from Washington to Johannesburg was scheduled to span about 16 hours, including a one-hour refueling stop in Dakar, Senegal.

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

For Bush, the flight marked the first time he had stepped foot on Air Force One since leaving the presidency nearly five years ago. He and the former first lady were already on board the plane in Washington when Obama arrived, skipping an on-camera greeting with the current president and first lady.

Bush has purposely tried to stay out of the public eye since leaving office. But he wandered back to the plane's press cabin for two lengthy off-the-record conversations with reporters, returning the second time with Laura Bush in tow.

Clinton is no stranger to the presidential plane, having traveled aboard Air Force One frequently as both first lady and secretary of state. And many Democrats have visions of her making many more trips aboard the plane, though they hope she'll be the one occupying the front cabin.

The White House invited all of the living American presidents to travel to South Africa on Air Force One. Former Presidents Bill Clinton and Jimmy Carter were instead traveling on their own, while 89-year-old George H.W. Bush was unable to attend the memorial because he can no longer travel far distances.

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