Duncan Aviation, the Lincoln, Neb.-based business aviation support organization with 1,864 employees at 39 locations nationwide, has again been named one of the 100 best companies to work for in America by Fortune magazine. Duncan, the only general aviation company selected by Fortune, ranked number 30 on the list, published in the February 4 issue. The ranking is up 32 places from last year’s number 62 placement. Two-thirds of the scoring is based on an employee survey. The remaining third of the score reflects Fortune’s evaluation of the materials the companies provide.