Conor McGregor has boarded a jet and is returning to the United States ... where he's scheduled to appear in an NYC courtroom to face charges for his attack on a UFC bus back in April.
McGregor is facing several criminal charges -- including felony criminal mischief -- for the April 5 incident at Barclay's Center when he threw a steel dolly at a UFC bus.
Several people were injured in the incident -- including multiple UFC fighters and staff.
Conor spent the night in jail and eventually flew back to Ireland.