This work is a contribution to the calculation of the basic data used in the direct simulation Monte Carlo in dry air (80% N2 and 20% O2). The basic data of this modeling are the collision cross sections, which are calculated by using a semi-classical model based on the intermolecular interaction potentials of N2/N2, O2/O2, and N2/O2. To validate this data, we show a comparison between the measured dynamic viscosities reported in the literature for different temperatures and those calculated. Another comparison is performed between the calculation of the smooth cylinder drag coefficients and the measurements, which also have been presented in the literature. These two comparisons showed an excellent quantitative and qualitative agreement and therefore they confirm the calculated data validity.