This article gives a holistic overview of the current CO2 reduction measures and analyses the effectiveness of measures that are feasible for implementation in the future. To achieve the objectives of the Paris Agreement, the aviation industry needs to implement reduction measures because of its forecasted growth and contribution to global warming. The focus is set on CO2 reduction measures, categorized in technology, operations, infrastructure/air traffic management (ATM), and market-based measures. The most promising long-term technologies to reduce CO2 emissions are hydrogen-powered aircrafts and sustainable aviation fuels (SAF). In terms of operations, CO2 emissions can be reduced through weight savings, either from fuel or payload. For every additional ton on board of an aircraft, an extra 3%–25% of fuel is necessary, depending on the route distance. From an infrastructure/ATM perspective, the goal is to decrease flight times and avoid holdings because every kg of fuel burned produces 3.16 kg of CO2 emissions. Market-based measures have a low impact as a reduction measure, but revenues may be used to accelerate the research and development of more promising reduction measures. The implementation of just one reduction measure is not reasonable. A global approach with reasonable incentives to support CO2 reduction measures is preferable.