There's really no worst air move on the Pits...
Nair is our safest aerial going by raw numbers, to a ridiculous point if we cross-up an opponent's shield. Least start-up. Most active frames out of all our aerials, and has the best active frames to commitment ratio too. Not many true combos but good for juggles.
Fair is one of the longest reaching aerials in the game, it's safe, good active frames, and kills though late.
Bair similarly has long reach, kills the quickest out of any aerial, does the most damage, and is the safest option if an autocancel isn't an option.
Uair is strong, has great active frames, it's great for juggles and can kill at not completely unreachable percents. Also true combos into Usmash, though it's not safe to just attempt.
Dair is also strong, can true combo into any other aerial including itself, spikes, acts like a Bair, Dair and Fair all at once, and ends within a shorthop.
IDK, Dair is the only one I could live without since it's sort of redundant, but at the same time it's really versatile too.