The rating on Tulsa Airports Improvement Trust, Okla.'s bonds reflects the following strengths: The strong (around 95%) origination and destination (O&D) nature of the airport; The moderately diverse air carrier base of Southwest Airlines (32.2%), American/American Eagle (23.9%), and Delta (10.6%); Solid financial performance, evidenced by 1.38 times (x) annual debt service coverage in fiscal 1999 from annual net revenues; A moderate cost per enplaned passenger of $5.32 in fiscal 1999; and Ten residual airline agreements, including an unlimited step-up provision, all expiring June 30, 2008. The rating also reflects the following concerns: Flat enplanement levels; A moderate debt burden of approximately $52 per enplanement after the series 2000 bonds are issued; and A weak additional bonds test, which is
