Deficits "larger than expected"
The world's airlines lost about $8bn in 2008, the International Air Transport Association (IATA) said.
The Association said this was $3bn more than the expected $5bn loss for the 12 months.
IATA said that in the fourth quarter of 2008, the loss of $4bn, was "larger than expected, because of recession and fuel hedging losses."
Airlines in Asia and Europe were now reporting "large losses", IATA said, adding: "Unlike earlier in the year airlines are now losing money at the operating level."
The figures, released in IATA's financial health monitor, showed that the equity market in airlines had fallen by 7% during February.
Stocks had been particularly badly hit in the US with the Bloomberg airline index down 28% in February and 42% for the year so far.
In Europe, stocks were down 3% for the month and had now fallen 20% since the start of 2009.
IATA said that airlines had been cutting capacity since last September but load factors had also been dropping from the same month.
But it said: "Airlines have found demand falling away faster than they have been able to cut capacity. In January average load factors were 2.8% points below the level of the previous year."
In January, airlines had put a further 73 aircraft into storage and retired 26 older aircraft.
Despite the delivery of 93 new aircraft during the month, the world fleet was now smaller.
Capacity was also being cut be reductions in both destinations and frequencies, IATA said.