Computational experiments have been performed for a few configurations in order to investigate the effects of external flow disturbances on the extent of laminar flow and wake drag. Theoretical results have been compared with experimental data for the AEDC cone, for Mach numbers from subsonic to supersonic, and for both free flight and wind tunnel environments. The comparisons have been found to be very satisfactory, thus establishing the utility of the present method for the design and development of “laminar flow” configurations and for the assessment of wind tunnel data. In addition, the present paper presents results of calculations concerning the effects of unit Reynolds numbers on transition. This phenomenon has been observed by a few experimental investigators but has been analyzed in detail for the first time in the present paper with the aid of the theoretical predictions. In addition to the AEDC cone, computations have been performed for an ogive body of revolution at zero angle of attack and supersonic Mach numbers. Results are presented for transition Reynolds number and wake drag for external disturbances corresponding to free air and the test section of the AEDC-VKF tunnel. These results have been found to compare quite well with wind tunnel data for cases when surface suction is applied as well as when suction is absent. Finally, the theoretical results reveal some interesting trends for transition Reynolds number for the ogive body under both free air and tunnel conditions.