For a non-flag officer in command of a unit of ships or aircraft, what is the assigned personal command pennant?

The personal command pennant for a non-flag officer in command of a unit of ships or aircraft is correctly identified as the broad and burgee command pennant. This type of pennant signifies the authority of the officer in command while distinguishing their unit, and is specifically utilized by officers who do not hold flag rank.

The broad and burgee command pennant is often flown from the vessel or aircraft, serving as a visual representation of the officer's command even in larger fleets where flag officers may be present. This pennant helps clearly identify the commander's unit and facilitates communication of their status and authority within naval operations.

The other options serve different purposes: the national ensign is primarily used to represent the nation and reflect sovereignty; the distinguishing flag is used by flag officers and generally illustrates their rank or command; and the commanding officer's pennant, while it may be relevant in certain contexts, does not specifically apply to non-flag officers as accurately as the broad and burgee command pennant does. Therefore, the broad and burgee command pennant is the correct answer in the context of a non-flag officer's command representation.