Passengers will face higher ticket prices if the decline in the airline industry continues, according to analysts.
Plummeting revenues following the US atrocities will lead to fewer carriers charging more for flights, says Justin Urquhart Stewart from 7 Investment Management.
Sabena is seeking bankruptcy protection, just a day after Swissair grounded all flights because of its financial difficulties.
Mr Urquhart Stewart says several other European carriers were facing a similar plight, with many airlines already in trouble before the September 11 attacks.
"At the moment there are too many airlines and not enough passengers. There will have to be changes and that will very likely lead to several going under."
He says Aer Lingus and Olympic Airways will face the toughest challenge in the current climate.
"We used to believe that national carriers could never go bust. That has now been proved painfully wrong.
"In the short term there will be some incredible deals for consumers as they fight to fill the seats available. This will change, however, and eventually there will be fewer flights from fewer carriers which will mean higher prices."
But the changes were very unlikely to lead there being just a few "King Kong" airlines able to charge what they like.
"There will always be entrepreneurs in the commercial market coming up to fill the market demand for cheaper flights," he added.