Germany's air safety agency DFS has now fully opened German airspace, the agency said Wednesday, adding it doesn't expect the volcanic ash situation to take a turn for the worse in the course of the day.

Based on information from the German weather service, DFS said "airspace contamination has significantly decreased, and will continue to decrease helped by the weather situation."

While some vision flights have been permitted in past days--flights in which pilots don't completely rely on automatic controls and instruments--the air quality situation now allows flights to operate as usual, DFS said.

Earlier Wednesday, Deutsche Lufthansa AG (LHA.XE) said it aimed to gets its systems running as fully as possible, and planned about 500 flights for the day. Chief Executive Wolfgang Mayrhuber said the airline would need about 48 hours, however, before Lufthansa can resume full service.

Mayrhuber, speaking at an industry event in Berlin, said Lufthansa's losses from the flight ban would be "considerable" but declined to quantify them. He said he doesn't think airlines will need a government bailout, but that the effects of the flight disruptions need to be discussed.

Germany's second-largest airline Air Berlin PLC (AB1.XE) said it would resume normal flight operations Wednesday and expected to carry out almost all scheduled flights, with full operation by the end of the week.

Company Web site: www.dfs.com

www.lufthansa.com

www.airberlin.com

-By Kirsten Bienk and Sarah Sloat, Dow Jones Newswires; +49 69 29725500 (Patrick McGroarty contributed to this story.)