Updated

From Texas to Washington to Baghdad , intense secrecy was the trademark of President Bush's unannounced Thanksgiving Day visit to Iraq.

Secret Service agents guarding his Texas ranch were not told when the president quietly slipped away in an unmarked car, officials said. The agents remained at their posts as Bush was hustled to Air Force One at Texas State Technical College (search), a former military base.

The plane's departure was explained by the ruse that it needed maintenance in Washington.

The level of secrecy — the tightest ever in recent memory — was intended to prevent terrorists and Saddam Hussein loyalists from trying to take a shot at the president.

First lady Laura Bush, preparing a Thanksgiving Day dinner, learned about the trip over the past few weeks, White House spokeswoman Claire Buchan said. The president, when talking by telephone from his ranch with White House chief of staff Andy Card (search), spoke in code words to keep the trip under wraps.

Bush's daughters, Barbara and Jenna, were not informed until just hours before he left. His parents, former President George H.W. Bush and his wife, Barbara, were not to be told until they arrived for Thanksgiving dinner, White House communications director Dan Bartlett said.

Bush's trip left several out-of-the-loop aides and even Secret Service agents — who learned about it at the same time as the rest of the world — stunned and a little angry.

White House aides emphasized the high security risks and said the trip would be abandoned if word leaked out.

"If this breaks while we're in the air we're turning around," Bartlett said.

Retired Air Force Maj. Gen. Don Shepperd, a military analyst, said he thought the risks "were absolutely minimal as long as secrecy could be maintained. And obviously all the stops were pulled out to keep this secret."

Shepperd said other factors lowering the risk were the fact that Bush's plane landed at night, lowering the threat of heat-seeking missiles, and it has the latest available equipment for repelling such attacks.

"The interesting question would be to know who decided this trip was a good idea," he said. "My guess it was the president himself who decided this was a good idea. But the point is, I think his security people probably almost had a heart attack when it was revealed, because of the risk."

Bush said with confidence that measures had been taken to ensure his safety and that of others.

Reporters who accompanied the president were not allowed to reveal Bush's trip until he was back on Air Force One and heading out of Baghdad.

Only a handful of aides knew in advance; Defense Secretary Donald Rumsfeld was informed last week. Secretary of State Colin Powell also was in the loop, as was national security adviser Condoleezza Rice, officials said. Rice informed her deputy, Stephen Hadley, on Wednesday.

White House deputy press secretary Claire Buchan didn't know about the trip when she briefed reporters in Crawford on the president's Thanksgiving Day plans.

Card invited two reporters on the trip Tuesday night on the condition that they keep it secret. Other reporters and photographers were brought into the secret on Wednesday, some of them searched out by White House aides in Texas just hours before the president's departure. In all, the press contingent included five reporters, a television producer and two-member camera crew, and five still photographers.

Bush made the 45-minute ride from the ranch to the airport in an unmarked vehicle. He joked about encountering traffic for the first time in three years, Bartlett said. Usually the president's motorcade speeds through red lights and traffic jams.

Bartlett said Bush's ranch departure couldn't have been detected. "If you were sitting outside the ranch waiting for the president, you would not have known the president had just left," he said.

The president stopped at Andrews Air Force Base (search) outside Washington to change planes and pick up some aides.

The switch took place in a huge hangar where the transfer was hidden from view. Bush underscored the secrecy. Standing at the top of his plane's steps at Andrews, Bush ordered reporters not to break telephone silence. He held his thumb and little finger to his face as if talking on the phone, and mouthed the words, "No calls, got it?"

He emphasized the point by slashing his hand in front of his throat and again mouthing "no calls." His order was unnecessary.

Reporters and photographers who had accompanied him from Texas were asked to take the batteries out of their phones. The reporters who joined in Washington after gathering at a hotel near the base were taken in an unmarked van to Air Force One's hangar. They were ordered to surrender their cell phones, pagers and other electronic devices, stashing them in yellow manilla-sized envelopes held by security officials until the plane was airborne.

Passengers were ordered to keep the plane's window blinds closed throughout the flight and were told that the aircraft would be flying in radio silence and would not be identified by its usual call sign, "Air Force One."

"People on the ground do not know this is Air Force One landing," Bartlett said.

The airport in Baghdad was blackened and Air Force One, once on the ground, could not be seen. Bush's motorcade traveled from the plane to the mess hall with lights out on most vehicles.