Air Craft Carriers had their advantages in old world wars, when planes could not fly great distances, a country used to move the command center on ship along with planes to enemy's borders and attack it
Now , same could be done with ICBM with advancement in science, and Missile technologies , countries can achieve similar results with usage of Inter continental Missiles and Long Range high altitude bombers which can fly 24 hours straight.
The Aircraft carrier , is still a useful tool to engage operations against nations , who do not have ICBM or Bombers , as its a means to intimidate them.
Nations constructed Aircraft carriers in early 1900's , and to imagine Pakistan in 2011 Cannot make such a craft is beyond imagination just takes some vision and ambition but over all we don't have a urgent need for it
At present due to financial crisis having a aircraft carrier is really out of our budget we can get 10 frigates, and 1-2 destroyers for same amount , and they can be more effective in operations at seas