The Belgian government previously decided that face masks are no longer mandatory in the plane, only in public transport and in healthcare institutions, but Brussels Airlines has stuck to it until now. At TUI fly Belgium, wearing a cap is no longer necessary.
More and more European countries are abolishing the obligation to use face masks on airplanes. The Dutch government does not want to abolish this obligation yet, because this would not be possible due to ‘European rules’, but Dutch airlines such as KLM and Transavia have largely stopped enforcement.
For both the Dutch and Belgian airlines, a face mask must only be worn if the country of destination explicitly requires it. Then they have no other choice.