Sources who have been with Brad since his separation with Angelina Jolie last week tell us ... Brad has made it clear ... he will engage in legal war to stop his estranged wife from getting what she wants -- sole physical custody, giving him only visitation rights.
For now ... they agreed Jolie would have the kids, while the L.A. County Dept. of Children and Family Services investigate the airplane incident.
Pitt could soon be vindicated after footage from Minnesota’s International Falls Airport shows the dad-of-six screaming at Maddox - but there is no physical altercation.
The FBI said they are "continuing to gather facts" regarding the claims, while Brad is said to be "cooperating fully".
If the allegations that he tried to physically go after his own son on the plane are true, he can rot. Such a weak man to go after his own child, Angie better get the kids 100%.