ABC News' Karen Travers, Sunlen Miller and Vija Udenans Report:
This evening President Obama took off from the South Lawn of the White House for his maiden voyage on Marine One, the helicopter that transports him on short distances and tonight takes him to his first ride on Air Force One, the 747 waiting for him at Andrews Air Force Base.
The President walked alone across the South Lawn grass, gave a quick wave to the press and boarded Marine One. But, first he stopped to shake the hand of the very startled, caught off-guard Marine who was standing at attention at the steps to the helicopter.
Joining President Obama for the ride were Chief of Staff Rahm Emanuel, Press Secretary Robert Gibbs, Trip Director Marvin Nicholson and personal aide Reggie Love.
Several junior staffers from the West Wing gathered on the track just off the South Lawn to watch the helicopter lift off.
They got there by walking out of the West Wing – and directly across the grass in the Rose Garden. When the helicopter disappeared out of eyesight, the staffers returned to their offices the same way they got there, right through the Rose Garden.
There were spectators visible in the windows of the Blue Room on the State Floor of the White House residence.
After boarding the presidential aircraft at Andrews AFB, Obama stopped by the press cabin in the back of the plane. He was wearing an Air Force One flight jacket and said his helicopter ride was "very smooth, very impressive," noting that he saw the Washington Monument.
Obama spoke to reporters on board about the stimulus plan and said it was important to make sure the recovery package is of significant size to do what is needed to create jobs. He said that every economist will agree if you have a trillion dollars lost, the range is $800 billion for the recovery plan. Obama said that is the scale and they are in range.
--Karen Travers, Sunlen Miller and Vija Udenans