Fighter jets are the main weapon of any aircraft carrier. Modern aircraft carriers can carry dozens of aircrafts, including helicopters and various types of fighter jets.
However, when aircraft carriers navigate for peaceful purposes, the presence of fighter jets on board is not necessary, as they may be at risk due to adverse weather conditions.
For this reason, any aircraft carrier has a special underground section designed to transport equipment, maintenance and special space to hide the fighters.
Worth to note that this section is not designed to accommodate all fighters, but it is able to accommodate most of them. The fighters are transported to the special section and vice versa using special lifts.
Thus, when an aircraft carrier does not have any fighter on board, it is not necessary to believe that it is unarmed. All the fighters were probably moved to the lower section and hidden there, where they could be moved to the surface very quickly if necessary.