You can't control the rockets like you can on the PT boat. In the hangar, you can choose between 23° or 45° angles, but once you launch the rockets are fixed.
The 23° setting intersects some aspects of AH gameplay in interesting ways. 23° will give you a range of 1000 yards which is also the range where plane range icons switch to fine granularity. It takes about 7.5 seconds from launch to impact at that range whereas it takes just over 8 seconds for a plane to complete its start sequence and begin rolling after a spawn.