The dramatic fall has been devastating for airlines and hotels which rely on corporate travellers to pay top dollar for premium cabins or rooms, which are typically booked much later than they are for leisure travel.
Coming into 2020, business travel activity had grown for 10 consecutive years, at an average rate of 5.1 per cent a year.
Rockport says many questions remain about the speed and shape of the recovery in business travel.
Uncertainty makes forecasting a return to normal for business travel a "monumental task".
The most critical factor will be the production and dissemination of Covid-19 vaccines, the analysis says.
Being able to inoculate the public and significantly slow the spread of the disease is key to making business travellers feel safe and ready to get back on the road.
Rockport's baseline 2021 forecast projects a 21 per cent gain in business travel spending following a 52 per cent plunge last year.
Most of the gains are likely to come towards the end of the year as vaccination of the global population ramps up. These gains will accelerate next year as the world enters the mid-to-late stages of recovery.
"This includes a significant pick-up in group meeting activity and international business travel. We expect annual spending growth to slow in 2023 and 2024, but to remain well above the historical average growth with annual business travel spending eclipsing $1.4 trillion by the end of 2024, just below its pre-pandemic peak of $1.43 trillion."
But businesses and business travellers must navigate the fallout of the pandemic - a global recession, constricted trade, the financial blow to travel suppliers, and a whole new level of duty of care.
"The pandemic has been devastating for business travel and it's clear our industry will take some time to recover given the challenges we're facing on multiple fronts," said Dave Hilfman, interim executive director of GBTA.
In New Zealand, Nick Queale, general manager Flight Centre corporate, said it was hard to predict when international business travel will make a full recovery, but 2025 was not an unlikely guess.
"But a survey of our customers conducted late last year showed 56 per cent of New Zealand businesses were already back travelling, and we'll certainly see that jump up once a transtasman bubble is confirmed.
"At the end of last year, our domestic corporate sales had exceeded 85 per cent of pre-Covid levels.
"For New Zealand based businesses, being connected to the world will always be important, and while videoconferencing is allowing us to fill the gap while travel is difficult, corporates will be among the first to be on a plane once restrictions allow it," said Queale.
The Rockport report says economic damage is palpable, with global real gross domestic product (GDP) down by an estimated 4.4 per cent in 2020, an unprecedented decline. In comparison, global GDP fell 0.5 per cent at the trough of the Great Recession.
The report says the global business travel sector has been hit like no other by the pandemic and this threatens to be permanent.
"Corporate management quickly pivoted to work-from-home policies and the use of technology to help stem potential losses from the valuable face-to-face interaction. As these shifts came to bear, many would-be in-person meetings shifted online.
"During the year, travel management policies tightened such that only the most critical of business travel took place. Virtually all meeting and event travel was cancelled or postponed indefinitely."
