Navies across the world are adding aircraft carriers to their fleet, refurbishing old ones and adding new inventories even as some experts have questioned the cost and the relevance of aircraft carriers in the changing military warfare.

Established naval powers, including Britain, France, Russia and the U.S. - already with the most number of carriers than all other nations combined - are beefing up their aircraft carrier fleets. Emerging economic groups belonging to the so-called BRIC, Brazil, India and China are also joining the league of nations with aircraft carrier capability.

Rear Adm. Philippe Coindreau, commander of the French navy task force that has led the air strikes on Libya since March 22, said navies across the globe want to project an image of power when building up their aircraft carrier fleets.

He added, "An aircraft carrier is perfectly suited to these kinds of conflicts, and this ship demonstrates it every day.

The U.S. Navy has 11 nuclear-powered carriers, mostly Nimitz-class vessels displacing up to 100,000 tons. And that is discounting the super-carriers already added in its fleet and new ones under construction.

Since WWII, these floating fortresses have been the backbone of U.S. sea power. They were also used in various conflicts the U.S. have been involved, including the wars in Korea, Vietnam, Iraq, Afghanistan and the conflicts in Kosovo and now in Libya.

The floating fortresses became the backbone of U.S. sea power after WWII, projecting military might around the world in crises and in conflicts such as Korea, Vietnam, Iraq, Kosovo and Afghanistan.

There is no clear data on the number of aircraft carriers in service in the world because some ships also qualify as such. Example are warfare ships, helicopter carriers or even cruisers or destroyers, which also fits the definition of carriers because they can serve as mobile air base with a flat deck.

But many military analysts are questioning the significance of aircraft carriers in light of new technology which makes them almost obsolete not to mention the cost of maintaining one.

They say that advances in anti-ship weapons have made aircraft carriers antiquated and even "white elephant" that are too expensive to risk losing in a war.

"These new technologies make it easier to target carriers from much greater distances," said Benjamin Friedman, a research fellow with the Washington-based CATO Institute.

Today's aircraft carriers have never been tested against modern navies with advance anti-ship capabilities.