Redeemable on ba.co for flights, hotel, car hire etc. When booking your flight, continue to the 'Review my flights' page, click the link at the bottom, then input your details and eVoucher code. You can use up to four eVouchers to pay for, or part pay for flights. If your flight costs less than the value of your eVouchers, we'll send you an eVoucher for the remaining amount. If the cost is more than the value of your eVouchers, you can pay the difference with cash.