We tested a new airborne imaging instrument to detect and measure methane emissions. Flying over controlled test releases in France, we compared our measurements with known release rates. The instrument detected emissions as low as 5.5 kilograms per hour in good weather and 1.45 kilograms per hour in ideal conditions. Our results show that better wind information is crucial for accurate totals. Our new instrument is important for helping target methane leaks in energy and waste systems.