To understand the aerodynamic impact of the ground deicing/anti-icing fluids on commuter aircraft, a wind tunnel test simulating takeoffs of a typical commuter aircraft was conducted at NASA LeRC IRT during early 1990. The results of the tests indicate that the fluids remain on the aerodynamic surfaces until well after the simulated takeoffs. Significant degradation on the maximum lift and climb gradient at climb out conditions were observed. The degradation in aerodynamic performance, especially at low temperature, indicates that many of the fluids tested were considered unacceptable relative to flight safety. However, increasing the time to rotation resulted in a substantial improvement in the aerodynamic performance to the extent that those fluids became acceptable.