The volume of video streaming traffic over the Internet has increased dramatically over the last 10 years. By the end of 2014, it is expected that 77% of the US internet traffic will be video streaming . In parallel, the last ten years have seen an incredible deployment of IEEE 802.11 technologies, also known as WiFi, at homes and public places. Although, the industry and research communities have given a lot attention to address the challenges of video streaming over wireless access networks (e.g., Cellular, WiMAX, WiFi), there are still interesting problems to address to enhance the user quality of experience (QoE). In this paper, we highlight the challenges that face adaptive video streaming over wireless access networks. Then, we propose a a heuristic cross-layer adaptation algorithm named E2E-MAC to improve the video client application response to changing conditions in WiFi environments. The algorithm, which runs on the client side, combines end to end (E2E) throughput measurements with MAC-based measurements from the WiFi link to choose the appropriate streaming quality - to request from the server. Simulation results have shown that our algorithm reduces the occurrence of buffer under-run, increases the average achieved streaming quality, and lowers the rate of lost video frames. This is achieved with a minor overhead on the client application's side.