Complex sentence: As Las Vegas casino/resort industry expanded during the 1950s, traffic increased; in 1959 the number of daily flights had gone from 12 to 73, and 959,603 passengers passed through the airport.
Split into simpler sentences: As Las Vegas casino/resort industry expanded during the 1950s, traffic increased. In 1959 the number of daily flights had gone from 12 to 73, and 959,603 passengers passed through the airport.