Airports across Europe resumed flight operations last night following the end of the ash ban placed by Britain's Civil Aviation Authority.
Heathrow Airport in UK began normal operations today.
British Airways and Virgin Atlantic Airways said they will operate all long-haul services from London.
Air France-KLM Group restored its scheduled flights after Charles De Gaulle Airport and Paris-Orly Airport in France resumed services.
Deutsche Lufthansa AG said it will operate about 500 flights on Wednesday after Frankfurt Airport in Germany officially reopened on 20 April.
Singapore Airlines, Korean Air Lines and Cathay Pacific Airways will also resume services to northern European regions.
Airports in Australia have also resumed operations with a Virgin Atlantic flight leaving Sydney Airport for London Heathrow at 2.19pm (AEST) today.
On 20 April, 25 flights from Pearson Airport in Canada left for previously closed airports and all departures for today are scheduled on time.
Air Canada cancelled 30 flights to Frankfurt, Munich and London, but resumed flights to Paris, Rome and Tel Aviv.
Denmark also reopened its airspace at 9:00 GMT today.