Every plane must overcome the resistance of the air. Under a project called LamAiR (laminar aircraft research), the DLR Institute of Aerodynamics and Flow Technology and the Institute of Structures and Design show how air drag can be significantly reduced: by perforating the outer skin of a vertical tail  with holes measuring a maximum of 50 micrometres in diameter through which air is drawn off, which reduces turbulence. By applying this concept to an entire aircraft, its total air drag may be reduced by around 15 per cent. The resultant improvement in fuel economy would reduce the cost of operation and facilitate compliance with increasingly rigid emission regulations.