Trespass in the UK does'nt realy exsist. If the machine was in a hangar, and he broke into said hangar with intention to either damage or steal anything, that would be be Burglary. If he walked across your garden and sat on your doorstep, you couldn't do a thing about it ! Good old British Justice
Conditional Discharge:
He was discharged on condition that he was a good boy for the next year or so and does'nt try to nick another Helicopter !
Hit em were it hurts most........In the Boll*cks !