Heathrow was having its busiest day for Olympics arrivals on Tuesday, with around 1,200 athletes and coaches flying into the west London airport as well as more than 3,000 other Games-related arrivals.
In total, Heathrow was handling around 217,000 passengers on Tuesday, including 99,000 arrivals.
Immigration queues for arriving passengers at Heathrow were reported to be moving smoothly.
More than 1,000 Heathrow volunteers, speaking more than 20 languages between them, are welcoming groups of athletes and officials from their planes.
London 2012 accreditation desks are operational in each Heathrow terminal, allowing Games-related passengers to collect their accreditation for the Olympic Village as soon as they arrive.
Motorists however faced long queues on Tuesday on routes where pre-Olympics modifications have been made to road layouts.
There were delays of up to an hour on the A13 between the Canning Town Flyover and the A1261 East India Dock Link Tunnel junction in east London.
There were also jams on the A12 southbound in Leyton in east London while there were 45-minute hold-ups on the A40 Western Avenue in west London.
The delays were less severe at these spots than they had been on Monday, suggesting that drivers were heeding the warnings by Transport for London to avoid driving in London in the run-up to, and during, the Games.
London Underground services were running without delays on Tuesday, but Monday saw a series of problems, including routes that will serve the Olympic site at Stratford in east London.
However, transport chiefs on Tuesday insisted they were not embarrassed by the failure of two train lines that caused major delays following a dress rehearsal of the London 2012 opening ceremony.
The closure of London Underground's Central Line and an Overground line affected the 60,000 people who had come to the Olympic Stadium on Monday night.
Transport Secretary Justine Greening rejected a suggestion that she should be embarrassed about the problems.
"I don't think that's right. We got everybody home," she said.
"It was a successful dress rehearsal but it shows on a transport system as complex as London's things do go wrong.
"What we showed last night actually was even when things do go wrong we still delivered a transport system for people to be able to get home.