'straight Outta Compton' Star Threatens To 'smack The F*** Outta' Passenger Before 1st Class Meltdown

"Straight Outta Compton" star Jason Mitchell's insane meltdown was ignited by an eavesdropping passenger -- who was in the first class seat ... Jason wanted so badly.

TMZ obtained new video of the crazy scene which shows Mitchell actually sitting in the economy seat to which he got bumped. Jason was on his phone telling someone about his ordeal, and a first class passenger overheard and apparently made a comment. That's when Jason erupted on the guy -- "Am I talking to you? F**king racist!"

As a flight attendant approached, things got more intense with Jason screaming, "I'll bat the f**k outta you! Unless you sitting next to children or anything else."

Amazingly, he calmed down after that, took his seat and promised to be good. In the video you see him put on his headphones and chill -- but when a Delta staffer announced he had to deplane so police could deal with Jason ... the rage returned.

As we first reported ... Delta says Mitchell had missed his original flight -- for which he had a first class seat -- and was flying standby. Police eventually detained him, but Delta refused to press charges.