"Why is this bird flying so slowly?"
Translation:Dlaczego ten ptak leci tak wolno?
"fruwać" is definitely a less common word, but we added it somewhere else, so added here as well.
"lata" would suggest that the bird is generally slow, for which you'd use "this bird flies".
So "lecieć" is present continuous whereas "latać" is present simple, just like "nosić" and nieść" respectively?