BUENOS AIRES — Judges overseeing Argentina’s most high-profile human rights trial sentenced 29 former officials to life in prison on Wednesday, in a case that documented the former military dictatorship’s widespread practice of killing civilians by throwing them from aircraft.

“This is a happy moment in the long fight for justice that has been going on for decades,” said Victor Basterra, 73, a former political prisoner held at the notorious naval base in Buenos Aires that was at the heart of the case. “It’s always satisfying to watch them get life sentences.”

The verdict capped the most ambitious effort to date to hold former military leaders accountable for abuses committed during the 1970s and 1980s, when several Latin American countries were ruled by right-wing military juntas. Prosecutors tried 54 former Argentine officials in the deaths or forced disappearances of 789 people, and presented testimony from more than 800 witnesses.

The court acquitted six defendants, including a couple of pilots, and sentenced the rest to prison terms that ranged from eight to 25 years. As the four-hour sentencing hearing concluded, the defendants avoided looking at former political prisoners and relatives of those who were killed, who were standing in the back of the courtroom.