Yettaw arrived in the US on Wednesday, looking exhausted and clutching a green bag as he was pushed in a wheelchair through Chicago's O'Hare International Airport.
"If I had to do it again, I would do it a hundred times, a hundred times, to save her life," he said in an interview with The Associated Press news agency after arriving in the US.
"That they locked her up, it just breaks my heart."
Yettaw testified during the trial that he swam to Aung San Suu Kyi's lakeside home in May to warn her about his "vision" that she would be assassinated.
Yettaw's latest remarks seem to indicate that he still believes his visit had somehow saved her life.
The former war veteran has been ill since his arrest in Myanmar in May and was seen wearing a blue surgical mask to guard against infection.
Yettaw had flown with Webb to neighbouring Thailand on a US government aircraft on Sunday and underwent medical tests at a private hospital in the capital, Bangkok.
At Chicago's airport, Yettaw's companion, who did not identify herself, said he was "very tired".
He flashed the sign language symbol for "I love you" and nodded and smiled when asked whether he was happy to be home.
Asked later if he would comment further, Yettaw said, "I wish I could talk more. I can't", and made a zipper motion across his mouth.
Yettaw, a Mormon who lives on a military pension from serving in the US army for about a year in 1973, travelled to Myanmar in early May and donned homemade flippers for a nighttime swim to Aung San Suu Kyi's lakeside home.
His actions landed both him and Aung San Suu Kyi in prison, and triggered a trial which drew international condemnation against Myanmar's military rulers.
As a result of the incident, the detention order for Aung San Suu Kyi, who has been under house arrest for 14 of the last 20 years, was extended by another 18 months.
Her two live-in aides also remain in detention because of the visit by Yettaw, who has been called a fool and a madman by some of Aung San Suu Kyi's supporters.