A federal judge in on Thursday also ordered 60-year-old David Alan Anderson to undergo a mental health evaluation.
Anderson is charged with possessing a dangerous weapon on an aircraft and retaliation against a federal officer by threat of murder.
Authorities say was removed from a plane in Salt Lake City before it left for Las Vegas on Sunday after he threatened to kill a passenger.
Officers found a knife in his bag and say he then threatened to kill law enforcement officials.
Anderson told the judge he had run out of his anti-anxiety prescription.