Witches are spell-casting humans who are the main focus in Flying Witch.
In Folklore[]
Witches have been seen to be magic-using humanoids, usually evil and donning brooms and faithful black cats and/or Familiars.
In Flying Witch[]
Witches such as Akane Kowata and her little sister are simply humans who use spells, Tariot Cards, and magical items. They are the manga's main focus, as many characters in general are witches and/or supernatural beings like Makoto's cat, Chito, who is actually a Familiar, and Kenny, Akane's Familiar cat.