The Netherlands and Belgium take turns fulfilling this task for a number of months. Recently, the QRA was with the Belgians, now until June 19, it is with the Netherlands.
Both fighter jets of the air force are on standby 24/7 for a mission. They can take off within minutes and intercept an aircraft. The QRA takes action if an aircraft enters the Benelux airspace without making radio contact.
The Dutch aircraft operate from Leeuwarden Air Base. The Air Operations Control Station in Nieuw Milligen monitors the airspace day and night and directs the F-35s. If an aircraft is detected entering the airspace without permission, the air combat control activates the QRA to intercept the aircraft.
Defence

Source published: 17 April 25
The Netherlands Again in Charge of Airspace Surveillance
The so-called Quick Reaction Alert (QRA) is once again in Dutch hands starting today. For the surveillance of the airspace of Belgium, the Netherlands, and Luxembourg, 2 F-35s are permanently on standby to be deployed.