Seville

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

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