The cross section for large p t jet production for transverse momentum 10≤ p t ≤20 GeV/c and rapidity 1.6≤ η≤2.6 in p– N ( p–`air') interactions is studied from the analysis of multicore Extensive Air Showers recorded in the EAS–TOP calorimeter. The projectiles are the leading particles interacting at atmospheric depths between 250 and 480 cm −2, the CMS energy of interaction being s ≈500 GeV. The slope of the p t distribution agrees with the expected one from the p– p ̄ collider data at the same CMS energy. The measured jet production cross section in p– N interactions with respect to p– p ̄ interactions is (dσ/dp t) pN jet =(dσ/dp t) p p ̄ jet ·A α with α=1.56±0.07 for A=14.7 (average mass number of `air' nuclei). Such value is compatible within the experimental uncertainties with the one obtained in p–nucleus accelerator measurements at s ≃30 GeV in the same range of transverse momentum and rapidity. No indication of increase of α with energy, i.e. of the entity of the `Cronin effect', is found.