Cosmic ray showers offer a mean to study flux, particle type and arrival direction of primary cosmic rays at high energy. Such showers are formed by successive and competing particle interaction and decay processes. Detailed understanding of hadronic and electromagnetic particle production processes is needed to link the observed shower characteristics to properties of the primary particle. In this contribution we discuss some aspects of hadronic interaction models used in extensive air shower simulation and the importance and complementary nature of accelerator and cosmic ray measurements for improving these models.

PACS numbers: 96.40.Pq, 13.85.-t, 13.85.Hd