V-Flyer

I need to book a one-way flight from NYC to London for my family of four.

One-way tickets appear to be more expensive than return tickets that depart on the same flight.

Are there any disadvantages to booking return tickets, but just cancelling the return leg?

Thanks

Sorry, and also the date that we need to travel on is fixed, but is there any advice in terms of which (hypothetical) date in the future to opt for the return leg in order to get the cheapest fare?

It happens all the time booking a dummy return date as it is as you've stated a lot cheaper. I would not book the return on a Fri/Sat/Sun as they often charge you more.

Airlines won't know you are on a one-way ticket, I have worked in travel for too many years and have done this for clients many times before.

Welcome to the world of airline ticket pricing [:)]

You won't be able to cancel as such, just don't turn up for the return and that's it.

Just be aware that immigration will do a whole lot of digging around and it they think there is reason to believe you plan on staying beyond the allowed time/plan on seeking employment, you mmight find the return ticket being used.

Just giving fair warning.

I have found that one way tickets are one of the few times it's a great idea to use miles to pay for a one way in Y. NYC is on sale at 25,000 miles and you can book a one way for 12,500 miles + taxes. Hopefully you have some miles, but if not you can buy 12,000 miles for 195. Taxes are 132.

If you have some time before you need to book, you can earn some miles pretty fast. If you drink wine, then each person could place a first order with Virgin wine and get 3000 points. Your 1st shop over 20 via the online shopping thingy gets you 500 points. You can also earn 6000 points with your 1st spend on the VS Amex Black card. If you done the shopping, bought the wine and successfully applied for the card today, you could have all the points on your account in about 8 weeks......

Or, you can buy 19,000 miles for yourself for 300 quid then 'gift' 19,000 miles from your sig other for the same, makes 38,000 which is three one ways for 600 quid plus the taxes. Then do the remainder however. BUT you'll then be arriving on a one way ticket which might / will arouse suspicion unless you a British citizen or have residency etc.

I would assume OP already has a confirmed mode of transport home. For me it was a cruise....