The objective of the boundary layer component of SGP97 was to determine the influence of soil moisture on the local surface energy budget, and the effect of mesoscale variability on the development of the convective boundary layer. The NRC Twin Otter and NOAA Long-EZ atmospheric research aircraft each made 27 flux-measuring flights over rural Oklahoma between June 18 and July 17, 1997. Since SGP97 was a multiscale experiment involving surface, tower, aircraft and satellite measurements, combining data from these various systems (to compute a water vapour budget, for example) requires estimates of the degree of correspondence between the measuring platforms. This paper presents the results of aircraft/tower intercomparisons made throughout SGP97. Wind and flux data from 30-m runs by the aircraft are compared with data from three towers: the 1.5-m ER01 tower operated by the USDA /ARS over rangeland near El Reno, the 4.5-m tower operated by the University of Nebraska over tallgrass prairie in northern Oklahoma, and the 3-m tower operated by NOAA/ATDD on rangeland south of Chickasha. An encouraging level of agreement is demonstrated in net radiation data and in the fluxes of momentum and sensible and latent heat, with more scatter in some of the C02 flux data. The results suggest that it should be possible to conduct special SGP studies of boundary layer processes with the aircraft and towers providing spatial and temporal coverage respectively