Barcelona

Air Europa flies BOS → SIN in both directions, with a through-ticket back to Barcelona. Economy Basic is hand baggage only; the four fares above it add a checked bag, lounge access or a lie-flat seat.

Turkish Airlines flies SIN → DXB → BOS in both directions, with a through-ticket back to Barcelona. Economy Basic is hand baggage only; the four fares above it add a checked bag, lounge access or a lie-flat seat.