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 )

Source:

State Symbols - Colors - Red and Blue: NC State Library

Links:

Cultural Symbols - 50 states