According to CNBC, more than two dozen bomb threats against passenger flights across Europe this week have prompted diversions, emergency landings and military escorts. Authorities have described the threats as malicious hoaxes, and no attacks have occurred. A threat naming a specific flight already in the air triggers international procedures requiring a prompt landing, evacuation and searches, aviation security consultant Wilfried Covent said. National authorities handle threat assessments and security measures in coordination with airlines, airports and law enforcement. A single diversion can cost an airline as much as $250,000, including expenses for replacement crews, missed connections and disruption to the day's schedule, aviation security professor Philip Baum told AP.