If the aircraft's characteristic length is 5 m, can we assume that the continuum assumption holds? Flight conditions correspond to an altitude of 30 km with static conditions T=231.24 K and P=1185.5 Pa. Molecular weight of air is 0.029 kg/mol, Avogadro's number N_A = 6×10²³ mol⁻¹, effective cross-section for air molecules (N₂ or O₂) σ = 10⁻¹⁹ m². Start by calculating the mean free path of molecules at the given flight conditions.