"Paying cash with Avios" typically refers to the Avios Part Payment option offered by British Airways and Iberia. When booking a flight on the official website, you will reach a payment screen where you can choose to reduce the total cash price of your ticket by "spending" a specific amount of your Avios balance. This is different from a "Reward Flight," which is a ticket bought almost entirely with points. With Part Payment, you can use as few as 1,000 Avios to save a small amount (e.g., £10) or larger amounts to significantly lower the fare. This feature is highly flexible because it applies to almost all commercial fares, not just those with limited reward seat availability. You simply log in to your Executive Club account before searching, select your flights as usual, and then use the slider or drop-down menu on the final checkout page to select how many Avios you want to apply toward the total cost. The more Avios you contribute, the less cash you will need to pay via your credit or debit card.