The UK's two busiest airports will partially reopen today as the volcanic ash cloud maintains a grip on airspace and causes fresh travel chaos for thousands of passengers.
Air traffic authority Nats said both Heathrow and Gatwick would be clear of the no-fly zone from 7am after being shut for most of the night, although flights at both airports would still be subject to restrictions, particularly Gatwick arrivals.
Elsewhere, flights have been grounded between 7am and 1pm at all airports in Northern Ireland, several in Scotland including Edinburgh, Aberdeen and Inverness as well as Cardiff, Swansea and Bristol airports.
In a 5am update, Nats said the volcanic ash cloud was continuing to change shape.
The air traffic body said: "Two key areas affect operations stretching from the South England to Northern Ireland, and over much of mainland Scotland to the Shetland Isles.
"As a result, no-fly zones have been imposed by the Civil Aviation Authority in these areas, for the period 7am until 1pm.
"Airports within the no-fly zones include all those in Northern Ireland, Ronaldsway, Edinburgh, Aberdeen, Inverness and Northern Scotland. Cardiff, Swansea, Bristol and Farnborough are also in the no-fly zone.
"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."