Activating airplane mode on a smartphone can slightly increase charging speed by disabling wireless networks and background activities that consume power. While this reduces energy usage, the difference is typically minor, ranging from a few minutes to about 10-15 minutes faster charging. Experts note that using a fast charger, a quality cable, and a wall socket offers a more significant impact. Heavy phone usage during charging, such as gaming or streaming, slows down the process more than leaving airplane mode off.