Photo: © 2010 AFP/AAP/JULIEN WARNAND

In the biggest disruption to flights since the 9/11 terrorist attacks, nearly the entire region has become a no-fly zone.

Tens of thousands of people have been left stranded across the continent, and the ripples are being felt as far away as Australia.

The travel chaos is all the result of Wednesday's eruption of the Eyjafjallajokull glacier volcano, which sent up a 10 kilometre high plume of volcanic ash that has drifted across Europe.

Authorities fear that the fine particles spewed out by the volcano could bring down planes, and are unsure when it will be safe to fly again.

"If volcanic ash particles are ingested into a jet engine, they accumulate and clog the engines," David Rothery, from Britain's Open University, told The Age.

"[In similar incidents in the past, planes] fell to within a few thousand feet of the ground before it was possible to restart the engines."