action aerial aerofoils air blue color colour diversity flock fly glide gliders group hang-gliders hangglider on the move outdoor parachutes paragliders sky soar sport summer suspend bridleway England english eroded erosion exercise forest Great Britain green landscape nature panorama path sign Soil Sussex track trail travel trees view walk warning wooden woodland clouds countryside destination direction farm fence field footpath hedgerow natural rural spring approaching danger hill imminent oncoming rainstorm storm