This week: How demand for flights to the United States affects fluctuating ticket prices

Q&A: Travel Unravelled

Nashville is no longer served non-stop from the UK (AP)

Q I'm thinking of taking my family to Nashville in September. We had previously looked and it was £700 each, yet today it's £570 for the same flights on the same dates. Any ideas why this is and any tips on the right time to book?

Huw Davies, Carmarthenshire

A Airlines have encouraged travellers to assume that the fare for a seat on a specific flight only ever increases as the departure date approaches. This rule applies fairly unerringly for peak times such as just before Christmas and just after New Year.

In some years, the summer follows this pattern, particularly across the North Atlantic – fares to Florida in July and August in previous years have topped £1,000 return.

This summer, though, the market appears weaker – and the airlines have blinked. Every flight on every airline has a predicted booking trend. The expectation might be that six months before the flight 25 per cent of the seats should be sold, three months ahead half are filled, and 90 per cent sold with a week to go before departure.

If sales are below trend, then fares are cut to stimulate demand. Peak-season fares to the eastern US, as you had observed, were originally priced at around £700. Over the past few weeks they have slipped lower, with the highly competitive London-New York link down to £550 return.

Nashville is no longer served non-stop from the UK, but there are connecting flights via a wide range of hubs. The price you pay will depend on demand for the transatlantic sector, whether Heathrow-Washington on United or Gatwick-Charlotte on US Airways.

It is possible that fares may slip further, but a price of £570 looks reasonable for September. Even though UK schools are back, Americans returning home keep demand high. So buy soon – and to maximise the value you get from the ticket, see how long a connection you can get in the hub city. For example, Chicago and Atlanta both have quick links into the city. If you can get an early-morning flight from Nashville on your homebound trip then you can spend a rewarding day in one of these cities, unencumbered by baggage (which you check straight through) before your overnight flight home.