Air passengers in England delayed by a volcanic ash cloud are facing major disruption, despite the flight ban being lifted over most airports.
Airspace above Bristol Airport and Farnborough Airport in Hampshire remains a no-fly zone.
The ban has been lifted over the rest of England, but passengers continue to face chaos as airports get back to running a normal service.
London’s Heathrow, Gatwick and City airports have resumed limited flights.
Gatwick is closed to arrivals until 1300 BST and departures are subject to restrictions.
Limited arrivals
Air traffic authority Nats said restrictions were needed because the London airports were close to the no-fly zone over Bristol.
Earlier, a spokesman said: "Heathrow and Gatwick airports will be clear of the no-fly zone, however restrictions will have to be applied due to their close proximity to the no-fly zone, particularly affecting Gatwick inbounds."
Eurocontrol, the European air safety body, said Heathrow arrivals would be limited to 30 an hour initially and it warned of significant delays.
Knock-on disruption was likely to continue throughout Monday, a Heathrow spokesman said.
Transport Secretary Philip Hammond told the BBC the government and airline industry were working together to find ways of enabling aircraft to fly safely through the ash cloud.
Manchester, Liverpool and Leeds Bradford airports have reopened but passengers continued to experience disruption to flights on Monday morning.
Passengers at Liverpool’s John Lennon Airport found their flights were still cancelled, despite the flight ban being lifted.
Margaret Palombella, 55, from Liverpool, said: "It’s been terrible. There’s just nothing going."
Robin Tudor, a spokesman for the airport, said flights had already been cancelled by the airlines, adding that people should not assume their flights would be taking off.
He said: "The restriction was lifted for this morning, but there is a difference between that and flights resuming as normal.
"Just because the restriction is lifted doesn’t mean the flights are back on."
Elsewhere, Birmingham, Norwich and East Midlands airports are open again, after suspending flights on Sunday.
The Department of Transport has warned restrictions are likely across different parts of the UK until at least Tuesday.
Network Rail has pledged to do everything possible to help stranded travellers make journeys by train.
Ash from the Eyjafjallajokull volcano has led to thousands of flights being delayed or cancelled across Europe since April.
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