Houthi rebels in Yemen may have acquired new technology that makes drones more difficult to detect and helps them fly farther, according to weapons researchers. The use of hydrogen fuel cells in the drones would enable them to fly three times their current distance and make it harder for sensors to detect them. The fuel cell components were found in a small boat offshore in Yemen and were made by Chinese companies. This new source of weapons components could increase the rebels' self-sufficiency and strategic capabilities.