The 2-4-1 works on British Airways, Iberia and Aer Lingus — and nowhere else. Here is exactly which airlines qualify, why the rest are excluded, and how to use the eligible ones well.
One of the most common misconceptions about the BA companion voucher is that it works across the whole oneworld alliance. It does not. The voucher is restricted to three airlines — and knowing which, and why, saves you a lot of wasted searching. Booking the right one of the three can also cut your cash bill.
What you’ll learn:
The British Airways companion voucher can be used on reward flights operated by just three airlines:
| Airline | Voucher valid? |
|---|---|
| British Airways | |
| Iberia | |
| Aer Lingus | |
| American, Qatar, Cathay, JAL, Finnair … |
All three are part of British Airways’ own airline group or its closest partners — which is exactly why they are the only ones that accept the voucher.
It is easy to assume the voucher works across the whole oneworld alliance, because you can spend Avios on partners like American Airlines, Qatar Airways and Cathay Pacific. But the companion voucher is a separate benefit with a much narrower scope. It is tied to British Airways and its sister airlines, not the alliance. Trying to apply it to a Qatar or American reward booking simply will not work.
If your heart is set on a partner airline, you can still redeem Avios there — you just pay the full Avios for both passengers. See our reward seats guide for finding partner award space.
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The two non-BA options are not just fallbacks — they can be actively better:
Our guide to booking Iberia to avoid BA surcharges explains the mechanics, and the surcharges breakdown shows what you will actually pay.
The core rules are identical whichever of the three you fly: two seats in the same cabin on the same flight for the Avios of one, taxes and surcharges payable for both, and the outbound must depart before the voucher expires. What differs is the booking route — some Iberia and Aer Lingus itineraries, and any open-jaw, may need to be booked by phone with British Airways rather than online.
Confirm before you commit. Availability, routing rules and surcharges vary between the three airlines. If in doubt about a specific itinerary — especially a mixed BA/Iberia trip — call the British Airways contact centre to check the voucher will apply.
Choose Iberia or Aer Lingus when they either serve your destination better or cut your surcharges meaningfully. Stick with British Airways when it offers the most convenient routing or the only two-seat availability on your dates. In all cases, the voucher’s value still comes from a premium cabin on an expensive route — the eligible-airline choice is about trimming the cash, not changing that fundamental rule.
Check any specific booking with the companion voucher calculator, and see the wider ranking of high-value trips in our best uses guide.
The AviosArcana Editorial Team
We decode the British Airways loyalty programme in plain English, cross-checking every figure against BA’s published rules. We only recommend products we would use ourselves — and we tell you plainly when a redemption is not worth it.