Business Travel News has announced the results for their Annual Airline Survey of corporate travel managers and for the fifth consecutive year Delta Air Lines takes the top spot. The carrier swept all 10 categories of the survey, earning the top score in each. Pulling into second place was United, much improved from its fourth place finish in last years survey. Southwest and American landed in third and fourth place, respectively, but trailed United by a hair. U.S. airlines have been raking in record profits this year, and that has translated into the capability to invest in network expansion, fleets and amenities. As such, 47.3 percent of the respondent base saw airline customer service improve, an increase of 10 percentage points over last year. Only 10.5 percent said airline customer service has gotten worse. To read the complete story, click here.