We calculate the CO2 flight mileage included in your Management Information by using guidance from the Department of Environment, Food and Rural Affairs (DEFRA).
This is based on the 'Great Circle' calculation, which is used to navigate ships and aircraft. The calculation works out the distance between two points on the Earth's surface and gives the shortest distance from A to B. DEFRA then add a 9% uplift to allow for routing and circling prior to landing.