Can you use just one of the airline tickets of a return booking?

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Most carriers, including BA, have strict rules when passengers fail to turn up for check-in (Getty)

Q Our family is going to the US this summer. Our 15-year-old daughter is travelling out separately with her school and travelling home with us. She is on a group booking with the school for the outward journey (they would not allow a different return date), but I have booked British Airways return flights starting at Heathrow to the US for myself, my wife and our daughter.

Our daughter will not be using the outgoing part of the booking I have made and she will not be using the inbound part with the group. Should I let the airline know?

Name withheld

A This could turn out to be complex and expensive, and I am sorry we were not in touch earlier so I could advise you on the pitfalls. The least expensive and stressful solution will be that she forgoes the flight she has to the US with the group, and travels with you on the date you have booked. She will lose the entire flight booked by the school’s travel company – who, by the way, have perhaps behaved poorly in not allowing you to book a separate trip back for her. But that will be the end of the downside.

If the dates don’t work, but the group is flying out on British Airways and the ticket you bought for her is changeable (for a fee of probably several hundred pounds), then that is likely to be the cheapest option.

If she must travel out with the group, then it gets very tricky. As soon as your daughter is a no-show for your outbound British Airways flight, the airline will – as its terms and conditions explain – cancel the whole itinerary. You might be able to reclaim a few odd charges, but that is all. Even if you call British Airways and explain the situation, they will either reiterate the “no-show = cancel” line or unhelpfully explain that they can offer you the chance to change your daughter’s ticket to a one-way US-London ticket for about three times what you paid.

The backstop, I am afraid, is to book a third ticket, this one starting in the US and going to London. If the route is served by Norwegian, then the airline will allow travellers as young as 12 to make the journey alone.

Every day our travel correspondent Simon Calder tackles a reader’s question. Just email yours to s@hols.tv or tweet @simoncalder