The major obstacle to having a sea basing carrier is cost. While the navy paid to convert several of its older ballistic missile subs to Special Operations subs, these subs are mainly carriers for cruise missiles. A sea basing ship would be almost entirely in support of army troops (as well as navy SEAL commandos.) So the navy would want SOCOM to share some of the cost, which would run to at least several hundred million dollars. If the war on terror is going to last a long time, as many believe, a sea basing ship would find itself in demand.
The U.S. Navy, looking to recast itself in a world where it is so powerful that it has no natural enemies, but still wants to feel needed, is now thinking of creating (from existing ships), not building, SeaBasing ships. The SeaBasing concept was actually tried, with great success, in late 2001, when the carrier Kitty Hawk left its air wing behind and took on long range helicopters of SOCOMs 160th Aviation Regiment. The Kitty Hawk then spent several months off the coast of Pakistan, serving as a floating air base for the Special Forces and commandos operating inside Afghanistan. Troops were flown in and out of Afghanistan from the Kitty Hawk. Supplies were sent in, and wounded troops brought out. This led to suggestion in early 2002 that a recently decommissioned carrier (the Constellation) be converted to a permanent SeaBasing ship. The idea died then, but now its been revived as SOCOM continues to take the lead in the war on terror. The navy has several retired (and held in reserve) carriers of the Forrestal class that, at 80,000 tons, are large enough (over a thousand feet long) to serve as a sea basing ship. A refit would largely consist of removing a lot of stuff (like the steam catapults and some of the engines, as a sea basing ship doesnt have to move 60 kilometers an hour like fast carriers do.) The sea basing ship would have lots of room for helicopters, UAVs and small fixed wing aircraft (that dont need a catapult.) The navy is also considering using C-130s from the sea basing carrier. Tests in the 1960s showed that you could safely have C-130s land on, and take off from carriers. But there really wasnt any need, and it hasnt been done since. But SOCOM uses C-130s a lot for its operations, and having these aircraft operating from the sea basing carrier would be a big plus.