Dream flight is ancient material. Artemidorus gave flying dreams substantial treatment in the Oneirocritica, reading them, as he read everything, by the dreamer's circumstances: the same flight promised different things to the traveller, the slave and the rich man, and the details of height, direction and company all altered the forecast. That a person might fly in sleep was not strange to his world; what mattered was what the flight foretold.
Freud classed flying among the typical dreams and traced it, like falling, to remembered childhood sensations of swinging and romping, while noting the exhilaration that usually attends it. Jungian writers read ascent more symbolically, as transcendence, overview and escape from the earthbound, with the caution their tradition attaches to flying too high above one's own ground.
Modern dream research added a distinctive fact: flying is one of the commonest deliberate acts in lucid dreams, the dreams in which the dreamer knows the dream is a dream, and for many practiced lucid dreamers flight is the first thing attempted. That finding says nothing about meaning, but it marks flying as one of the few dream acts people pursue for joy, and any reading of a flying dream has to make room for the pleasure of it.