  The understanding of the basic properties of the ultra - high energy
extensive air showers is strongly dependent on the description of the hadronic
interactions in a energy range beyond that probed by the LHC. One of the
uncertainties present in the modeling of the air showers is the treatment of
diffractive interactions, which are dominated by non - perturbative physics and
usually described by phenomenological models. These interactions are expect to
affect the development of the air showers, since they provide a way of
transporting substantial amounts of energy deep in the atmosphere, modifying
the global characteristics of the shower profile. In this paper we investigate
the impact of the diffractive interactions in the observables that can be
measured in hadronic collisions at high energies and ultra - high energy cosmic
ray interactions. We consider three distinct phenomenological models for the
treatment of diffractive physics and estimate the influence of these
interactions on the elasticity, number of secondaries, longitudinal air shower
profiles and muon densities for proton - air and iron - air collisions at
different primary energies. Our results demonstrate that the diffractive events
has a non - negligible effect on the observables and that the distinct
approaches for these interactions, present in the phenomenological models, are
an important source of theoretical uncertainty for the description of the
extensive air showers.
