| Cheap Flights: Austin to/from Saint Croix or Saint Thomas $263-$268 r/t [August-June] â Delta Delta has round-trip flights from Austin (AUS) to Saint Croix or Saint Thomas (STX/STT) for $263-$268 with a connection. Flights August to June. Weekends available. Origin/Destination reversible. Click for more details and booking links Cheap Flights: Austin to/from Saint Croix or Saint Thomas $263-$268 r/t [August-June] â Delta . | 