WASHINGTON — British Airways PLC was fined $300 million Thursday after pleading guilty to antitrust charges and admitting fixing some prices on international flights.

Britain's largest airline could have faced fines closer to $900 million but the Justice Department credited the company with cooperating in the case. A federal judge agreed.

"The company has produced hundreds of thousands of pages of documents of all kinds," U.S. District Judge John D. Bates said.

Representatives of British Airways pleaded guilty to two counts of conspiracy for colluding with rivals to fix fuel surcharges on international flights. Earlier this month, authorities in London announced $246 million in fines for the company in the parallel trans-Atlantic investigations.

As part of its plea deal, British Airways is admitting that between mid-2004 and early 2006, it colluded with Virgin Atlantic over the surcharges, which were added to fares in response to rising oil prices. Virgin Atlantic is not named in the Justice Department case and is not expected to face a fine in Britain because it reported the misconduct to authorities.

"As a foreign corporation with headquarters outside the United States, BA could have retained highly relevant documents in its foreign offices and refused to cooperate," prosecutors wrote. "It chose, however, to assist the United States early in its investigation in a highly significant and useful way."

Between 2004 and 2006, fuel surcharges rose from about $10 to about $120 per ticket for a round-trip long-haul flight on BA or Virgin.

The $300 million criminal fine was the second-largest antitrust sanction by the Justice Department since 1995. The largest antitrust fine, $500 million, was against vitamin giant F. Hoffman-La Roche in 1999 in a price-fixing case.