That article doesn't directly cite any IPCC report. This actual IPCC policy maker summary report[1] makes exactly 1 mention of air travel and it is to suggest structurally shifting some air travel to rail as a minor component of improving total transit emissions.
You're right, I cited the wrong article. The summary does mention air travel only once, but it does mention the 80% reduction figure, which seems nearly incompatible with air travel if everyone is expected to live with yearly emissions of ~3-4 tons of CO2.
[1]https://www.ipcc.ch/site/assets/uploads/sites/2/2019/02/SR15...