Flights across the UK are to remain grounded for a second day as volcanic ash from Iceland drifts across Europe.
At 0830BST, the air traffic control body Nats extended its unprecedented restrictions on UK airspace until at least 0100BST on Saturday.
However, a small number of services will be permitted into and out of Northern Ireland and western Scotland.
The continuing volcanic eruption caused cancellations across Europe amid fears the ash could cause engine failures.
Experts say the tiny particles of rock, glass and sand contained in the ash cloud from the still-erupting volcano could jam aircraft engines, as has happened in previous incidents of planes flying into plumes of volcanic ash.
Nats, which restricted all UK airspace at 1200BST on Thursday, allowed five flights overnight from North America into Belfast, Prestwick and Glasgow airports overnight as gaps in the cloud became apparent.
The Nats update at 0830 said that flights between Northern Ireland and the western isles of Scotland to and from Glasgow and Prestwick would continue until 1900 on Friday, on a case-by-case basis.
North Atlantic traffic to and from Glasgow, Prestwick and Belfast, it added, may also be allowed until then.
A further update is expected at 1330.