If convicted, Friedlander could face a sentence of up to 15 years in prison and a $250,000 fine.
The charges against the two men, contained in a nine-page FBI affidavit, allege that during a plane ride from Australia to Los Angeles, Grunwald and Friedlander fondled and groped a 15-year old American girl, sitting one seat away.
A woman who said she witnessed the alleged attack convinced the girl to tell the flight crew, and the two men were arrested as they disembarked in Los Angeles.
Grunwald, who would face the lesser charge of sexually touching a minor, was released on $10,000 bail and returned to New York. He was to appear in court June 26, but his attorney, Mitchell Egers, said there will be a delay.
The FBI affidavit said Friedlander told one agent that it was the girl who initiated the advances. "I shouldn't have done it, but it happened," he reportedly said.
Abzug denied that Friedlander, the father of five children, had made the confession, and questioned whether other statements were obtained lawfully.