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

It is called the "Broad and Burgee Command Pennant"

Explanation:

The Broad and Burgee Command Pennant are two different command with different indications. The Broad Command Pennant signifies of a group or squadron of ships, carrier air wing, or even an aircraft wing. On the other hand, the Burgee Command Pennant signifies an aircraft wing major subdivision or a division of crafts or ships.