Widely reported, rarely measured: unruly passengers on low-cost flights to Spain, 2020–2025

Abstract Unruly passenger incidents are a persistent concern for aviation security, yet event-level data for Europe are largely inaccessible because the official reporting system is confidential by design and national authorities publish aggregates that are not comparable with one another. This study examines what can be established from public sources about such incidents on low-cost flights to Spain, the largest leisure market in Europe, between 2020 and 2025. Cases were identified through a multilingual open-source search conducted in five predefined rounds with a saturation-based stopping rule, yielding 69 events coded across 18 variables and assigned to one of two documentary verification tiers. A second coder classified all events independently; agreement was substantial for diversion, behaviour category and physical aggression, and weaker for severity, which is therefore reported descriptively. Events concentrated on routes from the United Kingdom to Spanish island airports, 46.4% ended in a diversion or return, and physical aggression was documented in 44.9%. No characteristic was conclusively associated with diversion. Reading the events against a recently proposed proactive management framework showed that public accounts describe the middle of an incident, from early signs through escalation to the moment someone intervenes, while the antecedents of an incident and any organisational learning that followed it are absent from the record altogether. Set against official complaint counts, the sample captures a small and skewed fraction of recorded activity. The findings support harmonised event-level reporting in Europe.