The military said preliminary reports do not indicate the crash was caused by enemy fire, and the cause is under investigation.
The gunman had been married to the woman he killed, and the man fatally shot is believed to have been dating her, police said.
The forum capped a tumultuous day at the private university in Syracuse, New York, which has been roiled by a string of recent racist incidents on campus.
Navy SEAL Edward Gallagher was ordered dropped in rank after he was found guilty of posing with the corpse of a teenage ISIS fighter. Trump last week reversed the order.
A Republican on the House Judiciary Committee said Republicans would oppose the bill and that "it is even less likely that the Senate would take it up."