The attack appears to have involved only missiles. U.S. fighter planes, if used, would have had to contend with a modest web of Syrian air defenses and potentially more advanced types of surface-to-air missiles provided by Russia.
One of Assad’s more prevalent systems, the S-200, was used to target Israeli jets last month, but missiles were intercepted by Israeli defense systems. The S-200 has a range of roughly 186 miles, according to U.S. military documents, and can hit targets flying at altitudes of around 130,000 feet.
Russian S-300 and S-400 missiles, located primarily around Khmeimim air base in western Syria, have a shorter range than the S-200, but have more-advanced radar systems and fly considerably faster than their older counterparts used by Syrian forces. The S-300 has a range of roughly 90 miles and could also be used to target incoming U.S. cruise missiles.