Create a bold vector illustration of a circular shield inspired by American symbols, featuring a central eagle in flight, surrounded by stars and clean stripes. The eagle should be depicted with its wings spread wide, conveying strength and freedom, and centrally placed within the shield. Use a classic color palette of red, white, and blue, with metallic gray accents to add depth and sophistication. The design should include clean, thick outlines (4-6 points) for clarity and boldness. The background should be transparent or white, allowing the elements to stand out prominently. Ensure the illustration is created at a high resolution (300 DPI) for print quality. Incorporate a slightly distressed texture to the shield to enhance the vintage feel, giving it a weathered and timeless appearance. Consider adding subtle gradients to the eagle to create depth and dimension, enhancing its three-dimensionality, and incorporate texture overlays to simulate a vintage look, ensuring the shield appears authentic and rich in character.