Days after the incident, Jolie filed for divorce.
Brad Pitt is accused of “verbally abusing" and getting "physical" with his 15-year-old son, Maddox, last Wednesday, according to a report.
Pitt, Angelina Jolie and their six kids were on a private plane that left Nice, France, en route to Los Angeles. During a re-fueling stop at Falls International Airport in Minnesota, Pitt is said to have lost it.
A source close to the Fight Club actor tells People magazine he "was drunk and there was an argument between him and Angelina."
Maddox, their oldest son, stepped in to defend his mom and "got caught in the middle, literally. He stepped in front of Brad. There was a parent-child argument which was not handled in the right way and escalated more than it should have."
Witnesses claim the Ocean’s 11 actor appeared to be drunk and in a rage after the plane landed. He reportedly continued his rant on the tarmac and allegedly tried driving away in a fuel truck.
The flight reportedly continued on to Los Angeles and Pitt spent the night in a hotel. The plane incident was apparently the last straw, and Jolie filed for divorce five days later on Monday.
People magazine says Pitt is under investigation by The Los Angeles Department of Child and Family Services.
The source close to the actor claims he never abused his son, who was adopted as an infant in his native Cambodia.
"He is emphatic that it did not reach the level of physical abuse, that no one was physically harmed,” the source told People. “He did not hit his child in the face in any way. He did not do that; he is emphatic about that. He put his hands on him, yes, because the confrontation was nose-to-nose and was spiraling out of control."
Both Pitt and Jolie have reportedly been interviewed by investigators.
Read: Marion Cotillard Denies Affair With Brad Pitt, Says She's Pregnant
The Los Angeles Department of Child and Family Services told Inside Edition in a statement: "The law does not allow us to confirm or deny the subjects of our investigations."
The incident was also referred to the FBI, which has jurisdiction because it happened in the air.
"The FBI is continuing to gather facts and will evaluate whether an investigation at the federal level will be pursued,” the bureau told Inside Edition in a statement.
Sources say the Troy actor has not been permitted to see his children because there is an active abuse investigation.
Watch: An Inside Look at Brad Pitt and Angelina Jolie's 12-Year Relationship
