Less than a day after an Italian court acquitted her of murder, Amanda Knox was on a plane home to Seattle.

Knox, 24, left the prison where she had been held for four years on Monday night, less than two hours after the verdict was read. She was taken to Leonardo da Vinci Airport in Rome, where she boarded a flight to London Tuesday morning. From there, she will fly back to the United States.

Couldn't Wait to Get on Plane

She just couldn't wait to get on the plane. She told me that, even though she wasn't yet on the plane, she felt like she was already flying, Giulia Alagna, Knox's friend, told The Early Show on CBS.

In a letter to the Italy-U.S. Foundation, which promotes ties between the U.S. and Italy and supported Knox throughout the trial process, Knox thanked all the people who shared my suffering and helped me survive with hope; those who wrote, those who defended me, those who were close, those who prayed for me. I love you.

Knox was acquitted of murdering her roommate, Meredith Kercher, during a study-abroad program in Perugia, Italy, in 2007. Her ex-boyfriend, Raffaele Sollecito, 27, was also acquitted. It was a stunning decision by the appeals court, which reversed the guilty verdicts handed down by a lower court in 2009.

A Violent Crime, Still Unsolved

Kercher was brutally murdered in November 2007, and her body was found in the apartment she and Knox had shared. Prosecutors said that Knox, Sollecito and another man, Rudy Guede, had killed Kercher after a sex game went awry. But Knox and Sollecito denied any involvement, saying they were at Sollecito's apartment when the murder happened.

Guede was convicted on the basis of DNA evidence found in Kercher's bedroom, including on Kercher's body and in the bloodstains on the floor. He received a 16-year sentence and remains in prison.

There was much less evidence against Knox and Sollecito. Investigators said they found DNA on Kercher's bra clasp and on a knife in Sollecito's apartment, but in the appeals trial, court-appointed experts testified that the items had been handled improperly and could easily have been contaminated.

Kercher's family expressed disappointment at the acquittal.

While we accept the decision that was handed down yesterday, respect the court and obviously the Italian justice system, we do find now that we are looking at this again and thinking how a decision that was so certain two years ago has been so emphatically overturned now, Lyle Kercher, the brother of the victim, said at a press conference on Tuesday.

He and Kercher's other relatives said they still believed Knox and Sollecito were guilty, but they accepted the possibility that they might not be.

We don't want the wrong people put away for a crime they didn't commit, Stephanie Kercher, the victim's sister, said at the press conference.

Prosecutors say they intend to appeal to the Italian supreme court, but even if that court finds Knox and Sollecito guilty, Knox is unlikely to be extradited to Italy to serve her sentence. Prosecutors acknowledged that the acquittal on Monday meant Knox would probably remain free.

Knox said she even planned to visit Italy again as a tourist.

During the trip from Perugia to Rome, Amanda was serene, Corrado Maria Daclon, the secretary general of the Italy-U.S. Foundation, told CBS News. She confirmed to me that in the future, she intends to come back to our country.