SAN FRANCISCO (Standard&Poor's CreditWire) May 4, 2000--Standard&Poor's today assigned its single-'A' underlying rating to Tulsa Airports Improvement Trust, Okla.'s $11 million general revenue bonds series 2000A. The bonds are scheduled to sell May 8, 2000 with FGIC insurance, rated triple-'A'. In addition, Standard&Poor's affirmed its single-'A' rating on the trust's $10.27 million taxable general revenue bonds series 1999C, $14.67 million AMT general revenue bonds series 1999B, and $8.15 million non-AMT general revenue bonds series 1999A, all issued for the Tulsa International Airport. The outlook is stable. The bonds are secured by a senior gross revenue pledge. The rating on the airport's general airport revenue bonds reflects the following strengths: -- The strong (around 95%)