| Cheap Flights: San Antonio to San Salvador $355 r/t [June-April] â American Airlines / United / Aeromexico American Airlines, United, and Aeromexico have round-trip flights from San Antonio (SAT) to San Salvador (SAL) for $355 with a connection. Flights June to April. Weekends available. A negative COVID test result is required for entry/return. Click for more details and booking links Cheap Flights: San Antonio to San Salvador $355 r/t [June-April] â American Airlines / United / Aeromexico . | 