The world's airlines suffered €9.8bn losses last year.
The terrorist attacks on the US and the global economic made it the worst year ever for airline companies.
The International Air Transport Association (IATA) says Lufthansa took over from British Airways as the largest international airline with more than 29 million passengers carried last year.
Overall, however, Delta Air Lines was easily the largest, carrying 93 million customers - 86 million of those within the US.
Sharp declines in freight and passenger traffic and increased insurance and security costs "instigated a financial meltdown in the global aviation industry during 2001", says the IATA's World Air Transport Statistics report.
"The year 2001 was, without doubt, the worst year in the history of the air transport industry."
The number of passengers carried by airlines fell to 1.35 billion - a drop of 2.2% and the first decline since the Gulf War. Freight traffic was down 6.9%.