There is a de minimis exemption in subparagraph (j) of Annex I to the EU ETS Directive below which an entity ceases to be an aircraft operator covered by the provisions of the EU ETS. This exemption only applies to commercial air transport operators. Flights may also be provided by commercial operators without remuneration but this factor is not relevant when determining whether the de minimis threshold is exceeded.

In summary, all flights of a commercial operator which are not covered by any of the other exemptions in Annex I of the EU ETS Directive must be considered when assessing whether the de minimis threshold is exceeded.