BRUSSELS, Belgium — EU transport ministers vowed yesterday to reform the continent’s patchwork air traffic control system into a seamless European airspace and to establish binding rules to determine when volcanic ash makes it too dangerous to fly.

At an emergency aviation meeting, they vowed that the airspace reform was “a top priority” to reduce any possible future travel chaos caused by volcanic ash.

Underscoring how awareness of the danger has changed in only three weeks, EU Tranport Commissioner Siim Kallas said Tuesday’s ash cloud — which forced only Ireland and remote areas of Scotland to shut services temporarily — would have grounded huge swaths of Europe in mid-April.

Five days after much of Europe’s airspace was shut down, the EU agreed upon a three-zone system that freed lesser-affected areas so planes could fly.

“We looked at the maps today and we clearly can say if we had used the same methodology as (April) 14, we could close again a very large part of European airspace,” Kallas told reporters after the meeting.

Spanish Transport Minister Jose Blanco, who chaired the meeting, had maps of Tuesday’s volcanic ash cloud spreading over Ireland and Scotland, underlining the fact that aviation chaos could return and hurt Europe during the peak summer travel season.

The ministers called for a swift technological update on how to refine tests on the density of volcanic ash to determine when it was safe to let planes fly.

All these measures should fit in a new system where the 27 nations yield to a common, seamless airspace, which makes a decision for the whole of the continent.

“We want to give top priority to those measures which will accelerate the setting up of the single European sky,” said Kallas.

And after decades of bickering over the issue, Iceland’s erupting Eyjafjallajokull volcano has focused minds in Brussels — and yesterday’s latest swirl of ash didn’t hurt.

“The new cloud came at the right moment. It increased the pressure,” said German Transport Minister Peter Ramsauer.

“Now there is a consensus, and we can say that if tomorrow there is a crisis for whatever reasons, Europe gave itself political means in order to intervene more quickly,” said French Transport Minister Dominique Bussereau.

Airlines claim that a political overreaction kept far too many flights grounded — 100,000 in all — after ash from Iceland drifted over Europe after the April 14 eruption. The airport closures cost airlines over US$2 billion in loses and stranded 10 million passengers.

But ministers failed to decide how to compensate airlines, airports and passengers for their travel chaos.

Kallas said the weeklong crisis had caused losses of estimated at between euro1.5-2.5 billion (US$2 billion to US$3.3 billion) and included not just the airlines but other aviation-related sectors such as tour operators.

But he acknowledged there had been no real auditing of the losses so far.

Kallas has asked the EU’s 27 member nations to give airlines relief such as market-rate loans, but warned EU members not to follow EU state id rules designed to ensure fair competition between countries.

Kallas also wants to make sure that passenger rights on rebates and compensation because of the cancellations and delays are fully respected.

French tour operators and a leading consumer group met Tuesday to work out compensation for trips thwarted by last month’s airport closures. They signed an agreement saying the 80,000 French people whose trips were canceled because of the ash will not get their money back but can take the trips at a later date.