Fleas don’t have wings. They’re part of the insect order of Siphonaptera. The Greek prefix siphon translates to tube, and the suffix aptera literally means wingless. Nearly all ectoparasites of birds and mammals lack functional wings and can’t fly (e.g. fleas, ticks, bedbugs, and lice).

Though fleas lack wings, it’s believed they’ve descended from winged ancestors. Evidence suggests that fleas are derived from the order of Mecoptera (scorpionflies). Specifically, insects from the Boreidae family (snow scorpionfly) may be the ancient ancestors of fleas.

More Info: fleascience.com