TOKYO—Americans Michael Taylor and Peter Taylor pleaded guilty in Tokyo on Monday to the charge of helping former Nissan Motor Co. chief Carlos Ghosn escape Japan in a box aboard a private jet in late 2019.

Michael Taylor, a 60-year-old former Green Beret, and his son Peter Taylor, 28, were brought into a Tokyo courtroom in handcuffs surrounded by guards for the first day of their trial. After prosecutors read out a summary of the charge, the Taylors told the judge the prosecutors’ statements were correct. The defendants didn’t speak further on Monday, but a second trial session was scheduled for late June.

The Taylors appeared tired but otherwise in normal health after more than three months in a Japanese jail. The two were extradited to Japan from the U.S. in March, after their arrest in Massachusetts in May 2020. The Taylors were accused of aiding the escape of a criminal, an offense that carries a maximum penalty of three years in prison.

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At a press conference in Beirut, former automotive executive Carlos Ghosn said he ‘fled injustice’ in Japan. WSJ's Chip Cummins discusses what Mr. Ghosn said and didn't say. (Jan. 8, 2020) Photo: Maya Alleruzzo/Associated Press The Wall Street Journal Interactive Edition

Mr. Ghosn, who had been living in Tokyo while awaiting trial on charges of financial misconduct, escaped the country in late December 2019. He is living in Lebanon, which doesn’t have an extradition treaty with Japan.

At Monday’s court session, prosecutors outlined the story of how the Taylors and a third alleged accomplice, Lebanese-American George Zayek, orchestrated Mr. Ghosn’s escape, surprising the world and depriving Japan of the chance to put its most famous criminal defendant on trial.

The younger Mr. Taylor met Mr. Ghosn on the day before and the day of the escape, Dec. 29, 2019, prosecutors said. On the day of the escape, the elder Mr. Taylor and Mr. Zayek flew to Japan aboard a private jet carrying a pair of black concert equipment boxes. They later used one of the boxes to smuggle Mr. Ghosn aboard the jet, prosecutors said. Mr. Zayek hasn’t been arrested and is believed to be in Lebanon, where he is also a citizen.

The jet flew to Turkey, where Mr. Ghosn switched to another private plane that carried him to Beirut. In February, the two pilots who flew Mr. Ghosn to Turkey from Japan and a manager for the jet charter company that lent the aircraft were found guilty by a Turkish court of people smuggling. The judge gave each a suspended sentence of four years and two months.

A man who appeared to be Michael Taylor arrived at Narita International Airport on March 2.

A man who appeared to be Michael Taylor arrived at Narita International Airport on March 2.

Photo: Sadayuki Goto/Associated Press

Prosecutors said Mr. Ghosn, who was arrested in November 2018 in Tokyo, started planning his escape in June of the following year. They said that in October 2019, he transferred a total of $862,500 to accounts controlled by Peter Taylor to fund the escape, including the cost of the private jet.

Before their arrival in Japan, lawyers for the Taylors argued that they had not committed a crime under Japanese law and said they wouldn’t receive a fair trial in the country. Their lawyers cited the long periods of interrogation in Japan during which the accused can’t have their lawyer present, a system that critics call hostage justice.

Japan’s justice ministry and prosecutors have denied that they pressure people into making confessions. Defense attorneys aren’t allowed to be present during interrogations because it would interfere with the prosecutors’ work, according to the ministry.

Mr. Ghosn has said he is innocent of all the charges against him and fled Japan because he couldn’t get a fair trial.

In an interview in Beirut in May, Mr. Ghosn declined to comment on the Taylors’ role in his escape. “I don’t want to make anyone’s life more difficult than it is today, particularly when they are suspected of having helped me,” he said.

Mr. Ghosn said it wouldn’t surprise him if the Taylors made statements in line with Japanese authorities’ view of the case, but he would view such statements as made under duress.

“How can you trust a statement made by a person in a hostage justice system?” Mr. Ghosn said.

Write to Sean McLain at sean.mclain@wsj.com