North Carolina designated red and blue as the official state colors in 1945 (of shades appearing in the state flag and the National flag).
No specific meanings were attached to the colors in the legislation, but traditionally colors do have specific meanings in heraldic devices such as seals, coats of arms, and flags. Although the National flag also had no meaning specified to the colors, the Great Seal of the United States does:
Red - a symbol of hardiness and valour
White - signifies purity and innocence
Blue - signifies vigilance, perseverance & justice (also the color of the Chief )