Final answer:
The Mode 4 identification friend or foe/selective identification feature (IFF/SIF) mode enables operators to distinguish between friendly and potentially hostile aircraft.
Step-by-step explanation:
The mode that enables operators to distinguish between friendly and potentially hostile aircraft is called Mode 4. Mode 4 is a coded response mode, which means that an aircraft equipped with Mode 4 will respond to an interrogation signal from another aircraft or a ground-based system with a specific code. This code is used to identify the aircraft as friendly or potentially hostile.
For example, if an operator sends an interrogation signal with a specific code and a friendly aircraft equipped with Mode 4 receives it, the friendly aircraft will respond with the same code, indicating that it is a friendly aircraft. On the other hand, if a potentially hostile aircraft receives the interrogation signal, it may respond with a different code or not respond at all, indicating that it is not a friendly aircraft.