Complex sentence: Until 2002, Santa Barbara Airport was on the airline route between San Francisco and Los Angeles, served by Southwest Airways and its successors including Pacific Air Lines, Air West and Hughes Air West.
Split into simpler sentences: Until 2002, Santa Barbara Airport was on a major air carrier airline route between San Francisco and Los Angeles. The airport was served in the past by Southwest Airways and its successors including Pacific Air Lines, Air West and Hughes Air West.