Two common parts of the living cells are cilia and flagella. Their functions are not totally specific for all organisms. For instance, in some organisms, cilia and flagella are used for locomotion, while they are used for other things like mating, feeds, in other organisms.
Cilia are hairlike organelles or structures projecting from a eukaryotic cell. The same definition also goes for flagella. However, you can easily differentiate the two by comparing their size. Here, the hairlike structures of cilia are smaller than that of flagella meaning that flagella are longer than cilia.
While cilia also help prevent dust from getting accumulated in the breathing tubes, flagella help the sperm cells to move. Most multicellular organisms use cilia for locomotion and other functions, whereas flagella are mostly seen in gametes. The proton-motive force of the plasma membrane is the main source of energy for flagella, whereas ‘kinesin’ is the main source of energy for cilia.