The International Air Transport Association says 2009 saw the biggest decline in air passenger traffic since the Second World War.
Patronage fell 3.5% from a year earlier, while freight traffic fell by 10% as the downturn hit demand.
This year will also be difficult, with IATA estimating further industry losses of $US5.6 billion on top of the $US11 billion lost last year.
The director general at IATA, Giovanni Bisignani says governments must loosen rules on airline ownership to allow consolidation.
Air NZ passenger numbers down
Passenger numbers on Air New Zealand in December fell 3% to 1.2 million, compared to the same month last year.
The number of long-haul passengers fell more than 6%, due to reduced demand from Asia, Britain and North America.
Trans-Tasman patronage fell by 5.6% while domestic flights carried 0.7% fewer passengers.
Air New Zealand's group-wide yields fell nearly 10% for the financial year to date.
