The largest airports in both Denmark and Norway were forced to close temporarily on Monday (22 September) night due to the sighting of drones near their airfields.

Copenhagen Airport had to suspend all flights for around four hours because of the drone incident, while Oslo also had to close its airspace for a similar period of time. Both airports reopened early on Tuesday morning.

At least 35 flights heading for Copenhagen had to be diverted to other airports due to the incident, according to flight tracking site Flightrader24.

¡°Copenhagen Airport has reopened after being closed due to drone activity,¡± said the airport in a statement. ¡°However, there will be delays and some cancelled departures.¡±

Danish police told local media that the drones spotted near the airport were likely to have been operated by somebody ¡°showing off¡±, rather than intending to cause harm.

A drone was also spotted near Oslo Airport on Monday night with the airport closed for over four hours to allow for ¡°observation¡± before reopening at 4.30am local time.

Authorities in Denmark and Norway said they would co-operate to see if there is any link between the two drone-related incidents.

The latest disruption to European aviation come as several major airports, including London Heathrow, continue to deal with the impact of a cyber attack on check-in and boarding systems supplied by Collins Aerospace.

¡°Work continues to resolve and recover from an outage of a Collins Aerospace airline system that impacted check-in,¡± said Heathrow in a statement on Tuesday (23 September).

¡°We apologise to those who have faced delays, but by working together with airlines, the vast majority of flights have continued to operate.¡±

Brussels Airport, which has experienced the highest level of disruption since the cyber attack, said that it expected only a ¡°limited impact¡± on services on Tuesday with ¡°some flight delays and cancellations¡±.

The European Union Agency for Cybersecurity (ENISA) said that Collins Aerospace¡¯s systems had been subject to a ¡°ransomware¡± attack, which had scrambled automated check-in platforms.