On the use of inadequate airline data in mappings of a global urban system

Air transportation flows are potentially a prime data source in assessments of a global urban system. There are, however, two major obstacles that weaken their overall value. First, the potential usefulness of this data source is often assumed rather than properly discussed. Second, although a more refined discussion shows that airline data are indeed potentially useful, previous analyses have been hampered by inadequate and/or partial data.