According to PetMD, fleas lack wings and do not fly. However, fleas do possess robust back legs that help them leap onto hosts, such as dogs and cats.
In perfect conditions, the flea life cycle takes about 14 days. Humidity, temperature and the host all factor into a flea's life cycle, which consists of four stages: egg, larva, pupa and adult. Fleas can be very resilient, living through extreme environments for the right moment. When a pet is discovered to have fleas, all pets in the household must be treated, and bedding should be washed. Rugs should be vacuumed, and ideally, the entire house should be treated for fleas.