The Lental region in Pokémon Snap is full of exotic Pokémon for you to encounter in their natural habitat. You’ll be tasked to snag photographs of them as they go about their day or when you encounter them at night, using several items to have them strike specific poses or perform interactions. For The Flying Cacnea request, Rita wants to prove that she saw a flying Cacnea and needs your assistance. You can complete this request in the Sweltering Sands area during the day on Voluca island.
You can capture this photograph closer to the beginning of the Sweltering Sands location. There will be several sand tornados billowing about the area, and on the left side of the screen, a Cacnea will mind its own business in the sand. Eventually, the Cacnea will be swept up by the tornado, and you can capture it right at the center of the storm, being picked up and flying away.
This photograph is all about timing, and it can be pretty easy to miss. You do not have to use any items or try to prod Cacnea to move in any particular direction. It’s all about being there at the right time and having your capture fixated on the position.
Once you’ve captured the photograph, return to the research camp, click the ‘Y’ button to open up the requests, and turn in the quest to Rita under ‘The Flying Cacnea’ request.