Complex sentence: In 1963 Continental transferred all Roswell service over to Trans-Texas Airways (TTa) which in turn quickly upgraded its Roswell service with 50-seat Convair 600 turboprops.
Split into simpler sentences: In 1963 Continental transferred all Roswell service over to Trans-Texas Airways (TTa). TTA quickly upgraded its Roswell service with 50-seat Convair 600 turboprops.