Global flight delays is caused by airspace closures.

Many countries have closed their airspace to airlines and aircraft from Russia, barring them from landing, taking off or flying through their territories. This includes all of Europe, the UK and Canada. It’s possible more countries will do the same in coming days.
Russia has closed its airspace to airlines from multiple countries, preventing them from landing in or flying over its territory.
The airspace above Ukraine is closed to all commercial aircraft.
Flight durations may be extended due to route changes caused by airspace closures in an around Ukraine. Airlines have begun cancelling flights where the route is no longer viable.

If you’re travelling overseas in the next few weeks, contact your airline or travel agent to confirm your bookings. Be prepared for delays and disruptions.

Be aware that some borders may close without notice. Information may change and will be updated as details become available. You should also read the travel advice of the destination you’re travelling to – entry requirements may differ when entering by road, rail or air. Before leaving Ukraine, verify if the local authorities of your destination have implemented any restrictions or requirements related to this situation.

You’re encouraged to present a negative COVID-19 (PCR or RAT) test result taken as soon as possible to facilitate overland border crossings.