Complex sentence: On 21 December 2001, Reid attempted to board a flight from Paris, France to Miami, Florida, but his boarding was delayed because his dishevelled physical appearance aroused the suspicions of the airline passenger screeners.
Split into simpler sentences: On 21 December 2001, Reid attempted to board a flight from Paris, France to Miami, Florida. His boarding was delayed because his dishevelled physical appearance aroused the suspicions of the airline passenger screeners.