Final answer:
In the relationship, helicopter is a particular type of aircraft, helicopter is a subtype.
Step-by-step explanation:
In the relationship, helicopter is a particular type of aircraft, helicopter is a subtype. A subtype is a more specific category or class that is a part of a larger, more general category or class. In this case, the general category or class is 'aircraft', and helicopter is a more specific type or subclass of aircraft.