One of our residents thinks it is clever to fly UNDER the ATZ (quite legal but very silly)
Not only stupid but ignorant as well - it is not possible to fly 'under' an ATZ! By definition (ANO Article 258) an ATZ extends from the
surface to a height of 2000ft above the level of the aerodrome. The fact that a part of the surface within the boundary of an ATZ is below aerodrome elevation is irrelevant, it is still part of the notified airspace.