Aerodromes

thumb|Airport diagram for London Biggin Hill Airport|London Biggin Hill

airport with water runways and piers and/or ramps for seaplanes and amphibious aircraft

thumb|Alpe d'Huez Airport with sloped runway An altiport is an aerodrome for small airplanes and helicopters, situated on or within mountainous terrain. Altiports are generally characterized by having a runway with an atypical slope to fit in the local topography. Ultimately, this slope helps aircraft decelerating when landing and assists acceleration during takeoff. High altitude results in less lift available to aircraft wings, which requires aircraft to achieve higher speed at takeoff and landing. Such airfields with unusual physical characteristics are frequent in regions such as the Frenc