DALLAS — Think flying is getting worse? A pair of university researchers who track the airline business say it’s a fact. More flights are late, more bags are getting lost, and customers are lodging more complaints about U.S. airlines, government data shows. Dean Headley, a marketing professor at Wichita State and one of the co-authors of an annual report — now in its 25 th year — being released Monday, said passengers already know that air travel is getting worse. “We just got the numbers to prove it.” For the third straight year, Virgin America led the rankings. The niche airline with a limited route network was followed by Hawaiian Airlines and Delta Air Lines. Among other findings in the report: LATENESS: The percentage of flights that arrived on time fell to 76.2 percent last year from 78.4 percent in 2013. Best: Hawaiian Airlines . Worst: Envoy Air , which operates most American Eagle flights.