flag
旆 centers on a flag or banner, specifically a type of pennant or streamer used in ancient contexts.
旆 combines 㫃 (a flagpole with a streaming banner) with 巿, which likely contributes the sound. The character originally depicted a type of flag or pennant.
The left side resembles a flagpole with a cloth (方), and the right side 巿 looks like a fluttering streamer. Together they form a flag waving in the wind.
For ハイ, imagine a flag flying high in the sky: high -> ハイ, and the flag waves proudly.