 <unk> in the number of CAT operations , and in the number of airports they operate from , has resulted in a corresponding increase in Class A controlled airspace . Between 1997 and 2006 this area grew in size from 13 per cent of all airspace to 22 per cent nationally , and from 24 per cent to 43 per cent in airspace above England and Wales , leading to a perception within the GA community of being squeezed out . There are particular problems for GA around large airports , where Class A controlled airspace extends to ground level . The concentration of commercial operations and high demand for GA in the South East of England have also resulted in extensive areas of Class A controlled airspace there , which serve to channel uncontrolled GA operations through high @-@ collision @-@ risk hot spots . 
