For the popular British Airways American Express companion vouchers in 2026, the rule is quite strict: you must complete your outbound travel before the voucher's expiration date. It is not enough to simply make the booking before the deadline; the actual "wheels-up" moment for the first leg of your journey must occur while the voucher is still valid. For vouchers earned on the Premium Plus card, you have a 24-month window, whereas the standard card offers 12 months. If you are booking a return trip, the return leg can often occur after the voucher has technically expired, provided the departure from your home country was on time. If you fail to fly by the expiry date, the voucher typically vanishes from your Executive Club account without any option for extension, so early planning is essential.