Europe's air traffic control agency says commercial aviation is expected to return to nearly normal levels throughout the region by Thursday.
Eurocontrol released a statement Wednesday saying airlines's flight schedules should be operating at nearly 100 percent levels on Thursday, one week after volcanic ash from Iceland blanketed most of the continent, grounding flights and stranding millions of passengers.
The agency said nearly 80 percent of European flights were in the air Wednesday, and that trans-Atlantic air service had returned to normal.
However, the task of clearing a backlog of flights postponed or cancelled during the past week is expected to last at least several days.
An industry official says the shutdown cost airlines at least $1.7 billion. The head of the International Air Transport Association, Giovanni Bisignani, called the economic fallout "devastating" Wednesday. He urged European governments to help airlines recover lost revenues.
Some airline executives contend authorities acted too hastily in grounding flights.
The head of the International Civil Aviation Authority - the United Nations agency that deals with air safety - says there are no global standards currently to determine when it is safe to fly through an ash cloud. Particles of ash and volcanic glass can fuse inside jet engines, causing them to shut down abruptly.
Iceland's Meteorological Office says the volcano entered a new phase Tuesday, and that the plume of ash rising from the eruption is diminishing.
Businesses as far away as Africa, China and Japan have been affected by the pqast week's events, since companies have been unable to ship products to Europe.