<==o Apodidae (Kirskujat)
   |-- Cypseloidinae (Nokikirskujat[kiitäjät)
   `-- Apodinae (Varsinaiset kirskujat[Kiitäjät)

Reference(s):

Sibley, C. G. & Monroe, B, L., 1990: Distribution and taxonomy of birds of the world.
–Yale University Press, New Haven & London, 1990. xxiv-1111.