RAF Leuchars airfield started as a site for military balloons in 1911. It has also served as a Royal Naval Air Service fleet fighter station and a Coastal Command Airfield, and has been a Fighter Command Station since World War II. The base is headquarters to 43 and 111 Squadrons, plus Aberdeen, Dundee and St Andrews University Air Squadron, as to an RAF Mountain Rescue Unit and the Air Transportable Surgical Unit. Balmoral is one of the Royal Family's highland retreats. The original castle had been leased to the Royal Family from 1848. It was bought in 1852 by Prince Albert, the Prince Consort, for Queen Victoria. Albert drew up plans for a new castle, built between 1853-56, when the old castle was demolished.