fly upward
翀 centers on the action of flying upward, like a bird taking off or something rising into the air.
翀 combines 羽 (feathers, wings) with 中 (middle), likely suggesting a bird rising through the air. The exact historical development is uncertain, but the component choice fits the meaning of flying upward.
Feathers 羽 rising straight up through the middle 中 of the sky: 翀 means flying upward.
For チュウ, imagine a bird shooting upward with a sharp 'chew!' sound as it flies: chew -> チュウ, and the feathers 羽 rise through the middle 中.