Gate card: British Airways (BA)

The airline's policy: “Extra seat for comfort (Booking an extra seat for additional space)”

BA does not use the term 'customer of size' but publishes when you must buy a second seat: you'll need to buy yourself an extra seat for comfort if you're travelling in economy and need more space to easily fasten your seatbelt for take-off, landing or turbulence, OR if you're unable to fully lower both armrests of your seat (a fully lowered armrest between passengers is a safety requirement during take-off, landing and turbulence). BA will provide an extension seatbelt if needed. The extra seat keeps the adjacent seat free but doesn't always give additional seat width, and on some long-haul aircraft economy armrests only lift to 45 degrees. There is no free-second-seat scheme.

Refunds: Not published for extra-seat tickets on the page reviewed. (BA's paid-seating refund T&Cs on the same page cover seat-selection fees, not extra-seat tickets: refundable only if BA changes your seat unsatisfactorily, cancels the flight, you become exit-row ineligible with 48h notice, or after an upgrade; claims within 30 days of the last flight.)