"IAGOS (In-service Aircraft for a Global Observing System), one of the European Research Infrastructures (ERI) on the ESFRI roadmap and currently in its preparatory phase, is establishing a distributed infrastructure for long-term observations of atmospheric composition on a global scale from a fleet of initially 10-20 long-range in-service aircraft of internationally operating airlines. IAGOS will provide accurate, spatially highly resolved in-situ observations of greenhouse gases (GHGs) and reactive gases, as well as aerosol and cloud particles, in fact covering the essential climate variables (ECVs) for atmospheric composition as designated by the GCOS programme (Implementation Plan for the Global Observing System for Climate in Support of the UNFCCC, 2010). With the CARIBIC container, operated aboard an in-service aircraft on a four flights per month basis as part of IAGOS, a much larger number of parameters are routinely available. This project aims to make these valuable in-situ measurements available to the GMES Atmospheric Service in both near-real-time (for the IAGOS measurements) and delayed mode (for CARIBIC measurements). The interface between GMES and the IAGOS and CARIBIC communities is established in work package two, which also includes work on the development of database and graphical tools to make the data availalbe for the broader scientific community as well. The near-real-time provision of data requires the installation of Real Time Transmissin Units (RTTUs) on the in-service aircraft, which is carried out in work package three. Work package four focuses on the harmonization and systematic evaluation of the data quality collected on board the aircraft, and work package five supports the development of four new instruments designed to measure atmospheric quantities on board in-service aircraft, as well as a study to investigate the possible modular redesign of the IAGOS system to improve its flexibility in the future."