The interpretation of measurements of extensive air-showers generated in the upper atmosphere by ultrarelativistic cosmic-rays, in terms of primary particle energy and type, relies on the detailed modeling of high-energy hadronic collisions. The dominant source of uncertainty in the interpretation of air-shower data stems from the limited knowledge of (i) the total hadronic cross-sections, (ii) multiparticle production and (iii) the structure of hadrons at low parton fractional momenta (small-x), in proton-nucleus collisions in the hundreds of TeV range.The first LHC data have already extended considerably the energy range in which we have direct measurements available to constrain various model ingredients. In this presentation, we will compare the first LHC results on inclusive particle production in proton-proton collisions at energies sqrt(s) = 0.9, 2.36, and 7 TeV to predictions of various hadronic Monte Carlo models used commonly in cosmic-ray physics. While reasonable overall agreement is found for some of the models, none of them reproduces consistently the sqrt(s) evolution of all the observables. We discuss the implications of the new LHC data for the description of cosmic-ray interactions at very high energy and point out some measurements that can be done to further reduce the uncertainties of air-shower modeling.

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