This paper points out that existing data augmentation techniques are ineffective due to structural differences in wireless data, and systematically explores the potential and effectiveness of wireless data augmentation using generative artificial intelligence (GenAI). We begin by briefly reviewing existing data augmentation techniques and their limitations, followed by introducing the GenAI model and its applications in data augmentation. We explore the potential applications of generative data augmentation at the physical, network, and application layers, and present generative data augmentation architectures for each application. Specifically, we propose a general generative data augmentation framework for Wi-Fi gesture recognition, generating high-quality channel state information data using a transformer-based diffusion model. We evaluate the effectiveness of the proposed framework through a case study using the Widar 3.0 dataset and discuss future research directions.