According to Article 4.3 (b) of the EASA Basic Regulation, a Member State may decide to issue an exemption from the provisions of Regulation (EU) 139/2014 when the aerodrome in question handles no more than 10,000 passengers per year and no more than 850 movements related to cargo operations per year. Further details are also found in Art. 5 of Regulation (EU) 139/2014.
The term “passenger” is not defined in Regulation (EC) No 216/2008. Looking into other parts of that Regulation and Regulation (EC) No 965/ 2012, there is a differentiation between passengers and crew members. From this it follows, that passengers are all persons on board an aircraft, who are not crew members. This means that for the purpose of calculating whether a given aerodrome can be exempted, all passengers of a given year have to be counted, regardless of whether the operation was commercial or non-commercial.
This corresponds with the practice at Eurostat in its 2015 “Reference Manual on Air Transport Statistics”, where the following definition is given: “Air Passenger” any person, excluding on-duty members of the flight and cabin crews, who makes a journey by air. Infants in arms are included.”