He made the gesture on Thursday at Andrews Air Force Base before boarding Air Force One for the flight to Texas, where Ms Jenna Bush will be married on Saturday before about 200 guests at the family's secluded ranch.

Asked if he was excited, the president smiled and gave a thumbs-up.

'He's looking forward to it,' White House spokesman Gordon Johndroe told reporters aboard the plane as it flew from rainy Washington to sunny Texas. 'He's excited like any proud father is to see one of his daughters get married.'

'I think he's also going to make sure he gets a good night's sleep tonight so he can stay up late the rest of the weekend and enjoy all the activities.'

First lady Laura Bush was already at the ranch getting ready for the outdoor wedding on the 648 hectare spread in central Texas. Ms Jenna Bush, 26, is tying the knot with longtime boyfriend Henry Hager, who turns 30 on Friday.

The bride-to-be and Mr Hager of Richmond, Virginia, opted for a more low-key wedding, thinking a White House wedding would be too formal and stuffy.

The White House says it will be a closed affair. No details are expected to be released, although White House officials say the family might agree to release a photo or two of the wedding on Sunday.

'This is really a private event for the family,' Mr Johndroe said.

'I think the activities of the weekend are going to be really a private celebration for Jenna and Henry's family and friends.'

Mr Marvin Bush, one of the president's brothers, and his family flew down with Mr Bush on Air Force One. The group, along with White House advisers, hopped on the Marine One presidential helicopter with Mr Bush, who hurried them up with a wave and a smile.

On Thursday evening, the president and Mrs Bush drove about 8 kilometres from their ranch to dine at another ranch owned by Mr Donald Ensenat and Mr Joseph Canizaro, both from New Orleans.

Mr Ensenat, one of Mr Bush's fraternity brothers at Yale University and a former ambassador to Brunei, stepped down after six years as United States chief of protocol, saying the job was taking a toll on his family and wife, who divided time between Washington and New Orleans. He went into business with Mr Canizaro, a real estate developer, venture capitalist and Republican contributor.

The rehearsal dinner is slated for Friday night, and on Saturday, a barbecue lunch is being planned.

Mr Bush has joked that he has had little to do with the wedding planning - that he's mostly just expected to open his wallet. Vice-President Dick Cheney also joked about that on Thursday when he visited one of the government's financial centres in Philadelphia where the economic stimulus cheques are being processed.

'He's on his way to Texas for his daughter's wedding this weekend,' Mr Cheney said about Mr Bush. 'So you can bet he'll be writing a few cheques, too.'

Ms Tricia Nixon, one of President Richard Nixon's daughters, was the last child of a president to get married at the White House. She married Mr Edward Cox on June 12, 1971. Since then, other children of presidents have got married, but their weddings were not held at the White House. -- AP