EasyJet is testing an acrylic exterior polish which aims to reduce fuel burn by smoothing the aircraft's surface, reducing the build-up of dirt and lowering drag.
The nanotechnology-based polymer fills minuscule grooves and pits in the top paint layer to prevent any collection of debris in these areas and create a smooth surface.
The liquid treatment is manually applied to aircraft's entire exterior surface and then polished. It is typically less than 1 micrometre (0.001mm) thick, although exposed areas such as leading edges have been given a thicker layer for greater durability.
The coating adds approximately 4oz (113g) to the aircraft's weight but its manufacturer says it could reduce the specific fuel consumption by 1-2%.
EasyJet has coated eight of its aircraft with the treatment and is undergoing a 12-month trial.
The coating has already been used on military aircraft in the USA. One objective of the easyJet trial is to assess the coating's durability on commercial aircraft, which typically build-up flight hours much faster than military aircraft.
The preparation process involves washing the aircraft with a dicarboxylic acid to cleanse the paint surface and charge it with a positive polarity. The final coating is negatively charged to ensure that it fills all areas of unevenness during the curing.
Easyjet declines to comment on the cost of applying the additional coating.