To swoop often means moving easily and rapidly through the aiir. Swoop is a word generally used in conjunction with another. When followed by down, it means to dive or drop at speed, like a bird of prey. If swoop is followed by on, it implies making a sudden attack from a distance. Swoop up means to snatch everything in one go.
During my trip to Wales earlier this year, I watched choughs swooping through the air - just as my character Alice does in Firestarter. (I'll keep any similarities between our trip and the next chapter in the novel to myself!)