It is obligatory to wear a face mask in Copenhagen Airport as well as onboard the plane. When travelling to Denmark, different requirements apply depending on your country of residence and departure, as well as whether you have been vaccinated / previously infected. If you have stayed in a country with Covid-19 variants of concern within the last 10 days, you are required to be tested within 24 hours of entry and must self-isolate immediately. It is possible to be tested when you arrive at CPH. From 2 December, passengers from Doha and Dubai are required to be tested on arrival at CPH. Read more here: Travelling to Denmark as a tourist (coronasmitte.dk)