apparently, you didn't read the article. it was only the 2nd paragraph down. It took me less then 10 seconds to find it.

"The results are based on a poll of 406 travel managers and buyers who spend more than $500,000 a year on flights booked in the U.S. BTN gathers data across 10 categories, including price value, flexibility in negotiation of prices, complaint resolution, and customer service. 24/7 Wall St. reviewed the results of this year’s survey and added several factors that may be an indication of future performance, including airline revenue and profitability.

Delta took the top spot for the first time in the survey’s history".