Hamdan's lawyer said the Yemeni, who was held for nearly seven years before his trial, was simply a paid employee of the fugitive al Qaeda leader, a driver in the motor pool who never joined the militant group or plotted attacks on America.

Prosecutor Timothy Stone told the six-member jury of U.S. military officers who will decide Hamdan's guilt or innocence that Hamdan had inside knowledge of the 2001 attacks on the United States because he overheard a conversation between bin Laden and his deputy, Ayman al-Zawahiri.

"Virtually no one knew the intended target, but the accused knew," Stone said.

Hamdan, a father of two with a fourth-grade education, entered a not guilty plea to charges of conspiracy and providing material support for terrorism on Monday, the opening day of the first U.S. war crimes trial since World War Two. He could face life in prison if convicted.

United Airlines Flight 93 crashed in a field in rural Pennsylvania. U.S. officials have never stated it was shot down although rumors saying that abound to this day.

Prosecutors have said Hamdan had direct access to al Qaeda's leaders. Stone told the jury that Hamdan earned the trust of bin Laden during a trial period from 1996 to 1998 and helped him flee after attacks on U.S. embassies in East Africa in 1998 and the September 11 attacks.

"He served as bodyguard, driver, transported and delivered weapons, ammunition and supplies to al Qaeda," Stone said.

Hamdan was being tried in a hilltop courthouse at the U.S. navy base in Guantanamo Bay, which has been a lightning rod for criticism of the United States since early 2002, when it began housing a prison camp to hold alleged Taliban and al Qaeda fighters from the battlefields of Afghanistan.

CONTROVERSY OVER DETENTION

The war crimes tribunal system has been heavily criticized by human rights groups and defense lawyers, some of them U.S. military officers. Detainees have been held for years without charges. Washington has declared them unlawful enemy combatants not entitled to the rights afforded formal prisoners of war.

Hamdan was captured in Afghanistan and then held at Guantanamo for six years. Defense lawyer Harry Schneider described him as a poor Yemeni who lost his parents at a young age and lived on the streets, where he developed a knack for fixing cars.

"The evidence is that he worked for wages. He didn't wage attacks on America," he said. "He had a job because he had to earn a living, not because he had a jihad against America."

"There will be no evidence that Mr. Hamdan espoused or believed or embraced any form of what you will hear about, radical Islam beliefs, extremist Muslim beliefs," he said.

Schneider told the jurors the government would call none of al Qaeda's leaders as witnesses to testify about Hamdan's role in the organization. But he said the defense would call one who would say Hamdan "was not fit to plan or execute. He was fit to change tires and oil filters and clean cars."

The defense plans to question at least two accused September 11 planners, including alleged mastermind and al Qaeda number three Khalid Sheikh Mohammed, also held at Guantanamo.

The first two witnesses to take the stand were U.S. military officers who were in Afghanistan during the early days of the U.S. invasion in 2001.

Both addressed a the issue of whether Hamdan had surface-to-air missiles when he was captured at a checkpoint near Takhteh Pol in November 2001. Defense lawyers dispute the prosecution's contention that Hamdan had the weapons.

The missiles were found in the "trunk of a car driven by Mr. Hamdan," said one of the witnesses, identified only as "Sergeant Major A."

He said troops also found a mortar manual with "al Qaeda" on the front, a book by Osama bin Laden and a card issued by the Taliban to al Qaeda fighters and signed by Mullah Omar, the Taliban commander.

(Editing by Patricia Zengerle)