  More than a dozen wireless technologies are used by air traffic communication
systems during different flight phases. From a conceptual perspective, all of
them are insecure as security was never part of their design. Recent
contributions from academic and hacking communities have exploited this
inherent vulnerability to demonstrate attacks on some of these technologies.
However, not all of these contributions have resonated widely within aviation
circles. At the same time, the security community lacks certain aviation domain
knowledge, preventing aviation authorities from giving credence to their
findings.
  In this paper, we aim to reconcile the view of the security community and the
perspective of aviation professionals concerning the safety of air traffic
communication technologies. To achieve this, we first provide a systematization
of the applications of wireless technologies upon which civil aviation relies.
Based on these applications, we comprehensively analyze vulnerabilities,
attacks, and countermeasures. We categorize the existing research on
countermeasures into approaches that are applicable in the short term and
research of secure new technologies deployable in the long term.
  Since not all of the required aviation knowledge is codified in academic
publications, we additionally examine existing aviation standards and survey
242 international aviation experts. Besides their domain knowledge, we also
analyze the awareness of members of the aviation community concerning the
security of wireless systems and collect their expert opinions on the potential
impact of concrete attack scenarios using these technologies.
