Complex sentence: Between 1968 and 1984, Lockheed manufactured a total of 250 TriStars, assembled at the Lockheed plant located at the Palmdale Regional Airport in southern California north of Los Angeles.
Split into simpler sentences: Between 1968 and 1984, Lockheed manufactured a total of 250 TriStars. They were assembled at the Lockheed plant located at the Palmdale Regional Airport in southern California north of Los Angeles.