The row over airline subsidies and open skies escalated today with Emirates airline president and CEO Tim Clark criticising Delta Air Lines chief executive Richard Anderson recent comments saying the latter overstepped the line when he linked the 9/11 terrorist attacks with the Gulf carriers.

Anderson had told CNN’s Richard Quest that it was ironic Gulf airlines were complaining about post-9/11 financial benefits US airlines received since the attacks of 9/11 originated in Arabia.

Meanwhile, reacting to Anderson's comments, Delta has clarified: “Richard was reacting to claims the Gulf carriers have been making that US airlines received subsidies in the form of payments from the US government after the 9/11 attacks and the bankruptcy proceedings that resulted. He didn’t mean to suggest the gulf carriers or their governments are linked to the 9/11 terrorists. We apologise if anyone was offended.”

“The point Richard was making is this: Emirates, Qatar and Etihad have long tried to defend their government subsidies by characterising the 9/11 payments and Chapter 11 bankruptcy as subsidies. This couldn’t be further from the truth. The first was a one-time payment to US airlines in the aftermath of the US airspace closure after 9/11. Delta didn’t receive loan guarantees. The post-9/11 shutdown and its aftermath resulted in the loss of tens of thousands airline jobs and billions of dollars in debt and equity for investors. The bankruptcy proceedings that followed involved a completely transparent process with no government funding.”

Appearing on the Quest Means Business show of CNN yesterday (Feb 18) to discuss Anderson's comments, Clark said: “I’m not angry. I’m a little bit concerned that Mr Anderson crossed the line with what he said in regard to 9/11, which has caused great offense in this part of the world.”

Anderson claimed in his interview that Delta and its US major allies American Airlines and United Airlines had compiled a dossier of "documented evidence that cannot be refuted" regarding some $40 billion of subsidies he says Emirates, Etihad Airways and Qatar Airways have received.

Clark declined to comment specifically on the accusation, saying: "We have not had the benefit or the courtesy of being supplied with this report. I cannot comment on anything that we haven't seen."