Globally, the number of commercial airline passengers grew by 5.9% in 2018, according to a report released last week by the flight analysis firm ForwardKeys.

The ForwardKeys analysis of 2018 growth in worldwide airline passengers differs a bit from IATA's December estimate that the industry would see a 6.5% increase last year.

But IATA, too, sees the growth rate dropping this year. In December, the trade group cited a slower global economy, trade disputes and uncertainties caused by Brexit in predicting slightly less robust passenger traffic growth of 6% this year.