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LONDON, Sept 11 (Reuters) - Britain's two biggest airports, London's Heathrow and Gatwick, both reported their busiest months on record in August as they battle to be chosen by the government as the site for a planned expansion.
A government-appointed commission is due to make a recommendation on where to expand London's airport capacity next year, from a short-list of two options at Heathrow, to the west of London, and one at Gatwick, to the south.
Heathrow, Britain's busiest airport, said on Thursday over 7 million passengers travelled through its terminals in August, topping July's record-high of 6.97 million passengers.
That was 1.3 percent higher than in the same month last year, boosted by a 15.3 percent increase in passenger traffic with Mexico and a 9.3 percent rise with China.
Gatwick carried 4.4 million passengers, up 8.2 percent on August last year, helped by a 13.6 percent rise in travel to the United Arab Emirates, and a 34.8 percent increase in the number of passengers travelling to Istanbul in Turkey.
Heathrow is operating at 98 percent of its capacity, and has long been at the centre of a political tussle over airport expansion in the south-east of England.
The airport said on Thursday that larger, fuller aircraft were behind the growth in passenger traffic in August.
In September, business lobby group the Confederation of British Industry said that trade growth would be best delivered by a single British hub airport, an airport which airlines use for transferring passengers between flights. That view would favour expanding Heathrow.
Gatwick argues its expansion would promote competition between airports and airlines.
Frankfurt airport, Europe's third largest hub, also reported its busiest month ever in August, owner Fraport said on Wednesday. It surpassed 6 million passengers in a single month for the first time, with growth in demand especially coming from western Europe. (Reporting by Hannah Murphy and Sarah Young; Editing by Mark Potter)