[2]: 3–4 Modern flight management systems can calculate the optimum amount of fuel to tanker for given origin and destination fuel prices.
According to Eurocontrol, tankering on a typical 300nm flight can increase fuel consumption by approximately 2.21%, and tankering on a typical 600nm flight can increase fuel consumption by approximately 4.66%.
[2]: 2 Tankering can be limited by a need to arrive with a lower amount of fuel, to avoid exceeding the maximum landing weight, or to avoid cold soaked fuel frost.
While tankering reduces costs for airlines, it increases fuel consumption and therefore carbon emissions.
[4] A European Commission report in 2021 proposed banning tankering, and obliging aircraft to uplift fuel at all EU airports.