Precise global measurement of CO₂ in the Earth’s atmosphere is needed to understand carbon–climate feedbacks. Ideally we would measure from space 24/7 over all land and sea surfaces, in all-sky conditions, clouds, haze or dust and achieve near 100 % usable data. NASA-GSFC has developed a laser instrument to measure CO₂ from an aircraft flying at over 40 000 feet as a satellite precursor. Here we demonstrate this measurement capability, highlighting data in the presence of a variety of clouds.