How many pairs of wings do flies and mosquitoes have?

Flies and mosquitoes are both members of the order Diptera, which is characterized by having a single pair of functional wings. This is an important aspect of their classification, as the name "Diptera" itself means "two wings" in Greek. While they do possess a second set of wings called halteres, these are modified structures that assist with balance and stabilization during flight rather than functioning as wings. Therefore, the correct answer is that flies and mosquitoes have one pair of wings, which is critical to their ability to maneuver in their environment for feeding and mating. This distinguishes them from insects that have two pairs of wings, like bees and butterflies.