Commercial air travel has been dragged into the front lines of escalating conflicts across the globe, with airports, planes and airspace becoming the deliberate target of missile and drone attacks on a scale not seen before. Since the U.S. and Israel started the Iran war in February, major airports across the Middle East have been repeatedly targeted. Parked aircraft have been hit by missiles or falling debris from interceptor systems, killing crew members and passengers. The threat culminated Saturday in a Houthi missile strike at Riyadh’s King Khalid International Airport that killed at least 12 people and injured more than…