A 65-year-old Japanese man pleaded guilty Friday to assaulting a flight attendant aboard a Delta Air Lines flight from Tokyo to Honolulu, a federal prosecutor said.

U.S. Magistrate Judge Richard L. Puglisi accepted Sohei Yamanouchi’s guilty plea and fined him $2,500.

Yamanouchi hit the flight attendant once with an open hand and once with a closed fist after drinking four glasses of wine in business class Monday during Delta Flight 608 from Narita Airport, according to a criminal complaint filed in U.S. District Court. A crew member also noted that Yamanouchi had a glass of champagne before the plane departed.

After the meal service, the flight attendant was speaking to a passenger sitting behind Yamanouchi about a media player that wasn’t working. Yamanouchi rose from his seat and struck the flight attendant on her left shoulder with an open palm, then punched the same shoulder, shook his fist at her in a "threatening manner" and told her to "shut up" in English, the complaint said.

He was escorted back to his seat, and there were no other confrontations during the remainder of the flight. FBI agents arrested him upon arrival in Honolulu.

Yamanouchi was traveling to Hawaii to attend his son’s wedding at a Waikiki hotel, Assistant U.S. Attorney Michael Song said.

Through a Japanese-language interpreter, Yamanouchi apologized for inconveniencing the court. He told the judge he was trying to sleep but people were talking, so he told the flight attendant to be quiet, Song said. Yamanouchi said he wasn’t drunk and that he didn’t slap or punch the flight attendant.

His lawyer, Gary Singh, said Yamanouchi was scheduled to return to Japan Friday.