Overall passenger demand slumped 65.9% compared to 2019, which Iata characterised as "by far the sharpest traffic decline in aviation history".
International passenger demand fell more than three-quarters (75.6%), while domestic demand was nearly halved, down 48.8% on 2019.
Iata has 2021 may yet prove even tougher, at least at first, with much of the world under strict Covid lockdown – in many cases stricter than at any point last year.
This has impacted forward air travel bookings significantly, with bookings for future travel made in January down 70% on levels from a year ago.
Traffic in both November and December 2020 was heavily depressed too, down 70.4% and 69.7% respectively.
Iata’s baseline forecast for 2021 air travel demand is for a 50.4% improvement on 2020, which would return the industry to 50.6% of 2019 levels of demand.
However, the association said if tough restrictions were to persist owing to new variants of Covid, 2021 demand could be limited to just a 13% improvement on 2020, leaving the industry more than 60% down on 2019 levels of demand.
“Last year was a catastrophe – there is no other way to describe it," said Iata director general and chief executive Alexandre de Juniac.
"What recovery there was over the northern hemisphere summer season stalled in autumn and the situation turned dramatically worse over the year-end holiday season, as more severe travel restrictions were imposed in the face of new outbreaks and new strains of Covid-19."
De Juniac said optimism that the arrival and distribution of vaccines would lead to a "prompt and orderly" restoration of global air travel "had been dashed" by new outbreaks and variants.
"The world is more locked down today than at virtually any point in the past 12 months and passengers face a bewildering array of rapidly changing and globally uncoordinated travel restrictions," said de Juniac.
He said governments around the world must work with the industry to develop standards for vaccination, testing and validation that will give them confidence to reopen their borders to international travel, adding Iata’s Travel Pass digital health passport initiative could support this process.
"In the meantime, the airline industry will require continued financial support from governments in order to remain viable,” de Juniac added.
