NGS Style Manual‎ > ‎- F -‎ > ‎

flag, flagpole, flagstaff

Always lowercase:
            the United States flag

May be called a banner, a standard, or the colors.

Ensign, streamer, pennant, and jack are special kinds of flags.

Capitalize Old Glory, Maple Leaf, Tricolor, and Union Jack.

A flagpole is a permanent fixture; it carries a flag.

A flagstaff is borne by a person, ship, or vehicle

A flagstaff carries the colors (a flag borne by a person, ship, or vehicle).