Why? I would think that landing a U2 on a carrier would be easier than a regular fighter. All that wingspan and lift should let them approach the carrier at much lower speeds.
Same applies to takeoffs.
I suspect the bigger problem is the good old "interservice rivalry".
the landing hear of the U2 is more like a bicycle than a tricycle, and the wingspan requires special inserts called “pogos” so be retrieved or installed upon landing or takeoff. Additionally the U2 is supposed to be notoriously difficult to land due to visibility, thus requiring a chase car to act as spotters for the aircrew and a small ground crew to install the pogos. I’ve also hear that the wingspan can act against the pilot when trying to keep the a/c level, due to the fact it generates a lot of lift. All that being said, it’s pretty cool to see a U2 take off, looks almost like watching someone ride an escalator. Steep angle and fairly slow. I’ve also seen one take off with its nose angled at about 75 degrees.
On takeoff, young Navy gentlemen were necessary to hold the lady's wingtips up and level, but other than that, easy peasy.