For the past several years, air cargo has been facing major headwinds. An underperforming global economy and lackluster trade growth had the industry battling a long period of weak growth. But Boeing Co.'s recently released World Air Cargo Forecast indicates that those winds are shifting.

According to the report, world air cargo traffic, after a couple of years of drift, began growing again in the second quarter of 2013. By July 2014, it had grown 4.4 percent compared to the first seven months of 2013. The news was not good for all lanes, however. Air trade contracted between Asia and North America, intra-Asia, between Europe and North America, and between Africa and Europe.

Boeing expects the upward trend to continue. The report goes on to forecast even stronger growth in 2015 and 2016, predicting that the industry will grow by an average of 4.7 percent for the next 20 years. It predicts that air cargo services will more than double during the next 20 years and the number of airplanes in the worldwide freighter fleet will increase by more than half.

Boeing releases the World Air Cargo Forecast every other year to summarize the world's major air trade markets, identify major trends, and make predictions for the future. The next update will be released in the fourth quarter of 2016.