The outer pair of wings of beetles commonly are quite hard and not functional in flight. The ability to fly is not determined by the number or size of wings. Some insects with large wings, such as Dobsonflies and Antlions, are relatively poor fliers, while bees and wasps with smaller wings are good fliers. True flies are a large group of insects with only one pair of wings, although they have small balancing organs known as halteres where a second pair of wings might develop. The halteres vibrate with the wings and sense changes of direction.
Flight is one of the primary reasons that insects have been successful in nature.
They can truly hover also, which is an uncommon ability in insects. Flight in insects is gained by muscles, not attached directly to the wings, that move the wings indirectly by changing the shape of the thorax. A fascinating account of the speed of a Deer Bot fly, Cephanomvia pratti, was made by entomologist C. H. T. Townsend in 1926 by estimating the speed of the fly as it flew between mountaintops. Townsend published his findings, stating that the fly was able to accomplish a speed of 818 miles an hour. This figure has been repeated for decades, but is now believed to be quite impossible.