The International Air Transport Association says that airlines are likely to have lost more than $6 billion (£3.7 billion) in the first half of this year.

This number, an average of $1 billion a month, is twice the amount IATA forecasted in December that the airlines would lose in the whole of this year.

Carriers that made losses between April and June at a time when they would usually make 50 percent of their annual profits, IATA said.

However, the association says that passenger and freight numbers have already started to improve.

The two rose more than 3 percent in July from June, but will remain well below levels seen at the same time as last year.

IATA said that there had been a material improvement in July, but the future path is likely to be volatile and recoveries could be slow.

Throughout the world, European and Asian airlines fared the worse, with 12 airlines in Europe losing more than $1.1 billion, and Asian airlines losing about $1.6 billion between the months of April and June.

The global recession has had a significant effect on the travel industry, with business and leisure customers cutting back on travel, and companies transporting less cargo.