Whether you can use a companion voucher for premium seats in 2026 depends on the type of voucher you hold. For the British Airways American Express Companion Voucher, the rules were updated to be more flexible: if you earned the voucher via the Premium Plus card, you can use it in any cabin, including Club World (Business Class) and First Class, provided there is reward seat availability. If you have the standard (no-fee) card voucher, you are generally restricted to Economy (World Traveller) bookings. A key benefit of the "new" vouchers (issued after September 2021) is that they allow you to access a "wider pool" of business class seats that are not available to standard Avios bookers. Always remember that while the "second seat" is free of Avios, you must still pay the full taxes, fees, and carrier charges for both passengers.