The category "<rotary_aircraft_type-pl>" can be expressed as follows:

<rotary_aircraft_type-pl>

ah-1js

ah-1s

ah-64s

black hawks

ch-46s

ch-47ds

ch-53s

chinooks

civilian choppers

civilian copters

civilian helicopters

civilian heloes

cnn choppers

cnn copters

cnn helicopters

cnn heloes

cobras

frogs

kiowas

neutral choppers

neutral copters

neutral helicopters

neutral heloes

non-combatant copters

non-combatant helicopters

non-combatant heloes

oh-58ds

stallions

uh-60s