The Streamline Moderne or Art Moderne style is generally considered a later phase of Art Deco
, the earlier phase being Zigzag Moderne.
The Klingon battlecruiser had elements of both styles in surface treatment if not in overall form.
This is fascinating. I never thought of the Klingon ship in these terms, but there it is.
The 1920s and 1930s designs were meant to convey beauty, luxury, and sunny optimism, but Matt Jeffries smuggled them into a sinister, menacing alien ship. Neat!