Complex sentence: Youth Argosy was successful at first, sending more than 10,000 students abroad in 1949, but soon was troubled by new rulings of the Civil Aeronautics Board changing regulations about charter flights.
Split into simpler sentences: Youth Argosy was successful at first, sending more than 10,000 students abroad in 1949. However, it was soon troubled by new rulings of the Civil Aeronautics Board changing regulations about charter flights.