To land successfully, you have to be within the perimeter of the task group and be at a full stop. The way I like to do it is to speed out in front of the CV (to about where the Cruiser is) and then slow down by going into reverse. Watch your speed indicator, and at 0 turn off the engine. At that point you should be within the perimeter of the TG and can end your sortie with a successful landing.
You can also get a successful landing if you launch from a port, then return to that same port and make a full stop alongside a pier. I don't see this being used very often because of the distance of the spawn point.
If you're...
1. Very patient and drive your PT back to port.
Or
2. Defending the port you launched from, then this is a method you could use.