A couple of U.S. airlines have gone faster than their rivals in using intelligent booking and management systems, and it shows in their share price, according to an artificial intelligence consultant firm.

Stephen Pratt, CEO of Noodle.ai, tells Axios that Hawaiian Airlines and Southwest are far ahead of their industry rivals in incorporating learning algorithms into price and revenue management, route planning, and maintenance. When you tally up the daily multiple fare changes made for thousands of flights every year, they add up to billions. "There is no way 100 people on staff can change prices billions of times a day," said Pratt, who formerly was a senior executive on IBM's Watson team.

How to read the chart: the horizontal axis reflects the airlines' incorporation of machine learning, as appraised by Noodle in its eAI Index. The vertical axis is the companies' five-year share price compared with the industry average. On an absolute basis, Hawaiian's share price has soared by 6.5 times over the last five years, and Southwest's is up by six times. American's, conversely — an AI laggard in the group — has doubled since its merger with U.S. Airways in 2013.