Pope Benedict XVI arrived on time and without incident Tuesday at Maryland's Andrews Air Force Base to enthusiastic crowds and President George W. Bush.

The pontiff waved at hundreds of cheering spectators and shook Bush's hand. First lady Laura Bush and the couple's daughter, Jenna Bush, also greeted Pope Benedict on the tarmac. The group left a short time later in a motorcade.While en route to his first papal trip to the U.S., the pope expressed his feelings about the biggest divide American Catholics and the church face: the sex abuse scandal. "It is difficult for me to understand how it was possible that priests betray in this way their mission ? to these children," the pope said.

"I am deeply ashamed and we will do what is possible so this cannot happen again in the future," the pope reassured people during his flight from Rome.A welcoming ceremony marking the pope's 81st birthday is expected Wednesday at the White House. It will be the second time in history that a pontiff has visited 1600 Pennsylvania Ave. Pope Benedict will then travel to New York Friday.

Click here for team coverage about bands performing for the pontiff.