* H1 earnings up 8.8 pct to 555.2 mln stg
* Revenue up 8.4 pct to 1.16 bln stg
* To invest 3 bln stg over next 5 yrs
* CEO says ready to cope with peak Olympic arrivals (Adds company comment, Ferrovial shares, further details)
By Rhys Jones
LONDON, July 25 (Reuters) - Heathrow airport operator BAA has coped well with the influx of passengers flying into London for the Olympics and is confident it will handle the busiest day of Games flight arrivals so far on Thursday, its CEO said.
London Heathrow - Europe's busiest airport - expects to handle around 250,000 passengers on Thursday, including around 125,000 arrivals. Some 1,200 athletes are due to fly into Heathrow as part of around 4,000 Games-related arrivals.
"In terms of the Olympics it's been a case of so far so good," said BAA chief executive Colin Matthews, who has called the London Games Britain's biggest peacetime transport challenge.
"Thursday will be the busiest day of the lot for arrivals and we are prepared ... as we will be for the very concentrated demand we expect on August 13 which is the day after the closing ceremony and then for the Paralympics."
Earlier on Wednesday the PCS union called off a planned strike by UK border force staff.
The British government, which has drafted in more staff to man immigration desks during the Olympics, had sought an injunction to stop the planned border force strike.
Earlier this year passengers arriving at Heathrow suffered lengthy delays at passport control and complained of unmanned border control desks and the failure of iris scanners brought in to speed up the processing of arrivals.
Matthews said BAA's handling of the Olympics influx proved its crisis management processes have improved over the last 18 months.
The airport was criticised in December 2010 after its runways were closed and hundreds of flights were cancelled due to snowfall and freezing conditions.
Earlier on Wednesday BAA posted an 8.8 percent rise in first-half profit, squeezing more growth from its busy Heathrow hub.
The business, owned by Spanish group Ferrovial, reported earnings before interest, taxes, depreciation, and amortisation (EBITDA) of 555.2 million pounds ($862.03 million) in the six months to the end of June with revenue up 8.4 percent at 1.16 billion pounds.
Revenue was boosted by higher airline fees and a 2.4 percent rise in retail income, it said.
Heathrow handled 33.6 million passenger in the period - up 2.2 percent on the first half of last year - and helped by strong north Atlantic traffic which increased 4.7 percent.
It expects to report full year EBITDA of 1.27 billion pounds on revenues of around 2.5 billion pounds, in line with its previous forecasts.
Shares in Ferrovial were flat at 8.407 euros by 1000 GMT, valuing the company at around 6.16 billion euros.
BAA, which also owns Southampton airport in the south of England, and Glasgow and Aberdeen airports in Scotland, said it planned to spend 3 billion pounds over the next five years further expanding Heathrow's terminal 5 and building a new baggage handling system in terminal 3.
The operator completed the enforced sale of Edinburgh airport earlier this year and will learn on Thursday whether its appeal against a Competition Commission (CC) ruling that it has to sell Stansted airport was successful . ($1 = 0.6441 British pounds) (Editing by Sarah Young)