Counter Measures. 4. Air-borne troops are particularly vulnerable during and immediately after landing, and at this stage they can be readily dealt with provided attention is paid to the following points:(a) Aerodromes should be carefully defended with automatic weapons permanently manned and sited to cover the landing ground. Temporarily unoccupied aerodrones should be made unusable by moveable obstacles (b) Local mobile reserves should be maintained in each area for immediate counter attack, and stronger regional reserves, fully mobile, should also be available in support.