This article evaluates the accuracy with which the performance of a multiuser multiantenna system can be predicted with and without considering cochannel interference and noise (Gaussian, α‐stable, and Cauchy) using a site‐specific three‐dimensional (3D) ray tracing algorithm as well as with statistical models with Gaussian and Nakagami‐m channel models in small to medium sized aircraft. These models expand on previous statistical channel models such as the hyper‐Rayleigh model by including the simultaneous effects of cochannel and adjacent channel interference, antenna matching, efficiency, directivity and polarization as well as (for the 3D model) site‐specific multipath effects. Measurements and comparisons are made in a metallic‐bodied Beech Baron BE 58P and a composite structure Rockwell T‐39 Sabreliner. It was found that the 3D ray tracing model provides a mean capacity within 1% of those measured in the two aircraft in the presence of interference and noise. This was closely followed by the Nakagami‐m distribution (m = 1.4), which was within 1–3% of measured capacity in the presence of interference and within 6% for a combination of interference and noise and the Gaussian model which was within 6% of measured capacity in the presence of interference and within 11% for a combination of interference and noise. The Cauchy noise degraded the capacity more than the other types of noise in the aircraft, providing a lower bound for capacity in an aircraft system. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1137–1144, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25939