Passengers have been advised not to travel to the airport
Southampton Airport cancelled all its Monday flights as ash from a volcanic eruption in Iceland continued to drift across England.
The air traffic control body, Nats, said no flights would be allowed in or out of UK airspace until at least 0900 BST after a new cloud was detected.
Passengers have been told not travel to the airport and to to contact their airline for more information.
The UK's emergency committee Cobra met on Monday to discuss the problems.
Discussions were also being held over whether the Royal Navy could help ferry stranded Britons back home.
Gordon Brown has spoken to the Spanish Government about the feasibility of some Britons being flown into Spain, before a possible journey by sea to the UK.
The Hampshire and Isle of Wight Air Ambulance was grounded but is now operational.
No flights have left the Southampton Airport since airspace was closed at midday on Thursday.
Nats imposed the restriction because of the danger the ash poses to aircraft.
Tiny particles of rock, glass and sand in the cloud could damage engines.
Officials warn that European airspace could be disrupted for several days.
The volcanic eruption under a glacier in the Eyjafjallajoekull area of Iceland is the second in Iceland in less than a month.