Formidable Shield is happening again this year, from May 9-27, which will mean large parts of North Atlantic airspace will be closed to all flights for several hours at a time. The first closures we know about are happening May 9-12 from 09-21z each day, SFC-UNL, in a big area off the west coast of Scotland. So maybe expect some weird looking NAT Tracks those days. There might be more airspace closures after May 12, but these will only be announced by Notam 24hrs prior.
Dig