The purpose of this document, Deliverable 2.1, is to describe the sources of data required by the H2020 coordination and support action DATASET2050. Data requirements have been categorised into seven broad groups to support WP3 and WP4: demographic; passenger demand; passenger type; door-to-kerb; kerb-to-gate; airside capacity and competing services. The current scenario is well supported by existing datasets, however the two future scenarios require modelled data