Complex sentence: In 1963, the company, renamed as Spantax S.A., grew as it began to schedule transatlantic charter flights, and expanded its fleet, operating DC-3, DC-4, DC-6, DC-7 piston-engined aircraft.
Split into simpler sentences: In 1963, the company, renamed as Spantax S.A., grew as it began to schedule transatlantic charter flights. Spantax expanded its fleet, operating Douglas DC-3, DC-4, DC-6, and DC-7 piston-engined aircraft.