I'm off to the U.S. next month from the UK and have already booked my return flight home for October 2014. Now I'm trying to book my flight from the UK to the U.S, as it works out way cheaper to book another return flight than just a one-way ticket. Can I book the return flight & use it next year as part of a second trip?
Yes, there's nothing stopping you.
From my understanding of the question, you have a need for:
- flight to the US (A)
- flight back (B) - already booked
- and are considering (C) another flight back to be combined with A to make a return ticket, which you'll use at a later date.
All your tickets are just that - tickets for flights on day X, Y or Z. If you take it or not, the airline is getting your money. The only issue with return flights is if you don't take the first leg there, they'll usually cancel your return ticket. However as long as you take all these flights, you can.
And then you're wanting to book a new ticket (D) to the US next year, to be used BEFORE C? No problem, but you may want to book a flexible return for C, just in case you want to change the date. Also some return tickets must be within a year, so the dates might have some boundaries for you, which you'll find when you come to book. This is one time a travel agent may be of use to ensure you don't make any mistakes.
But yes, it is a valid option.
Your first obstacle with a far future return date will be the airline having to make sure your visa/wiaver status allows you to stay that long in the USA. Airlines are mandated to check that aspect and required to deny boarding if you don't qualify.
Why not cancel the one way return ticket and apply its value towards your next trip and simply buy the cheaper round trip ticket for this year.