NEW YORK — A group of hackers calling themselves “Lizard Squad” has taken down several popular online video game networks and possibly diverted an American Airlines jet carrying a Sony executive.

Over the weekend, Blizzard Entertainment, CCP Games, Riot Games and Sony have done maintenance to bring their networks back online.

The hackers, speaking publicly on Twitter, claimed responsibility for attacking the PlayStation Network and others, disrupting the ability of millions of gamers to play together online.

According to the targeted companies, hackers flooded their networks with illegitimate traffic — a strategy known as a distributed denial of service attack. The FBI said it was investigating.

The hackers slammed the following game networks:

Battle.net (World of Warcraft, Starcraft II, Diablo III) EVE Online League of Legends PlayStation Network and Sony Online Entertainment

On Sunday, Sony said both its services were still under repair but assured customers no user data was exposed. The other networks did not immediately return requests for comment.

When John Smedley, president of Sony Online Entertainment, acknowledged the “large scale” attacks on Twitter, he came under fire as well. Knowing that Smedley was on a flight from the Dallas area to San Diego, the hackers made a veiled threat about bombs on his plane.

“We have been receiving reports that @j_smedley’s plane #362 from DFW to SAN has explosives on-board, please look into this,” the group said to American Airlines on Twitter, pairing that with images of the Sept. 11, 2001 attacks.

The plane was diverted to Phoenix Sky Harbor Airport.

The FBI later released this statement: “The flight landed without incident. Passengers were safely removed from the plane.”