More than half of the world’s airlines have grown their operating margins in the last six months, with some of the largest growths coming from the US and Europe. 

The US was the main beneficiary of growth in airline revenue growth, rising by more than 20 percent. 

US airlines’ revenue grew by more then $1.3 trillion in the past six months compared with $1 trillion in 2014, according to the Bloomberg Intelligence report. 

Germany and Japan also saw the biggest increase in revenue. 

“The growth of the US airline industry is unprecedented and the trend in other key markets such as the UK and China is set to continue,” said Chris Bockenby, global head of airline consultancy at research firm Aviation Analytics. 

German airline WOW Holdings Ltd.

increased its revenue by more $2.5 billion in the six months to March 31 from the same period last year. 

British Airways Group Plc, the country’s second-largest carrier, saw revenue growth of 20 percent in the same time period, up from a flat 18 percent in 2014. 

Air New Zealand Holdings Ltd., which is in talks to buy British Airways, also saw revenue grow by 10 percent.

The Netherlands, meanwhile, saw its revenue grow more than 17 percent.