At the conclusion of COP21, the UN’s aviation agency, ICAO, and the aviation sector itself committed to substantial climate action in 2016. Now is the time to evaluate whether they followed through on that commitment. The two measures adopted in 2016 – a CO2 standard for new aircraft and a global market based measure to stabilise emissions at 2020 levels fall far short of what the Paris Agreement requires. Neither will have a meaningful impact on aviation emissions. Much more is needed – both greater ambition at ICAO, but also developed countries must go first and take serious action to reduce emissions from the aviation sectors which dwarf emissions from developing countries.