New fears over the ash cloud coming from a volcano in Iceland have grounded flights in and out of Ireland.
The National Air Traffic Services said: "Based on the latest information from the Met Office and the Civil Aviation Authority, NATS advises that, due to a heavy concentration of volcanic ash, a no-fly zone is in place in the west of Scotland and Northern Ireland, including some airports in the Western Isles from 0700 (local time) until at least 1300 (local time)."
"Apart from the no-fly zone, normal air traffic control operations are expected within Scottish airspace during this period, including Scottish airports, although some regulation may be required in light of operational experience.
"Conditions around the movement of the layers of the volcanic ash cloud over the UK remain dynamic. NATS will continue to monitor the latest Met Office information and the CAA's updates on the density of the ash cloud across the UK.
A spokesperson from Manchester Airport said last night: "Around 12 flights will be affected between Manchester Airport and Ireland during this period so passengers travelling to Ireland tomorrow should check with their airline before coming to the airport.
"Transatlantic flights that fly across Ireland will not be affected because the ash contamination is not at altitude.
"There is no indication at the moment that this ash cloud will affect UK airspace. Current advice from weather and air traffic control experts is that if the ash cloud moves over parts of the UK mainland, contamination levels are likely to dissipate which means that other than flights to and from Ireland, we expect Manchester Airport to operate normally."
Flights operating in and out of Blackpool International are continuing as scheduled. Liverpool John Lennon Airport said flights are now operating normally but advised passengers to check with their airline.
Restrictions on UK flight travel were lifted on Tuesday 20 April this year, due to the volcanic ash cloud.