Bat and bird wings have the same function and the same origin (they are modified limbs) so they are analogous and homologous organs. Whale fins are a modification of the posterior limbs while fish fins although having the same function do not come from modified limbs; so they are analogous but not homologous structures.
Evolutionary homology suggests common ancestry while biological analogy relates to the concept of evolutionary convergence, the appearance of similar features in evolutionarily distant species that explore the same type of environment (in the mentioned case, the aquatic habitat).
