As in the real world. You can only be current on one aircraft at a time. If you switch to another aircraft you have to go through a full refamil program.
The days of the 2nd WW when you just "kicked the tyres, checked Pilots Notes for stalling speed" are long gone.
Looking at his log books, my father flew 56 Royal Navy Fleet Air Arm types from the Seafire XV culminating in the Sea Vixen.
I do remember, when I was 16 years of age, Dad for 3 evenings reading the Sea Vixen Pilots Notes that were about 3 inches thick. Seafire XV was 44 pages!