Lifting restrictions on nighttime flights meant to maintain quiet in neighborhoods around airports would help airlines repatriate stranded passengers and get delayed freight deliveries to their destinations, he said.
Kallas warned EU member states not to grant airlines state aid other than loans at market rates or guarantees as a way of improving their immediate cash flow problems.
"This must be granted on the basis of uniform criteria established at the European level," he said. "It cannot be used to allow unfair assistance to companies which is not directly related to the crisis."
The closure of a large chunk of European airspace due to the volcanic eruption in southern Iceland caused the cancellation of more than 100,000 flights, and left 10 million passengers stranded.
Kallas told reporters he had briefed the European Commission about the economic impact of the weeklong crisis. He said it had caused losses of estimated at between euro1.5-2.5 billion.
Kallas has called an emergency meeting of EU transport ministers May 4 to fast-track the wholesale reform of Europe's fragmented air traffic system.
"Europe needs a single regulator for a single European sky," he said, adding that the first elements of the so-called Single European Sky could be in place by the end of 2010.
Unified airspace would also put the skies under one regulatory body instead of leaving decisions to dozens of individual countries -- one of the key sources of confusion in the volcanic ash crisis.