helicopters 272 air force 112 military aircrafts 91 aircraft construction 89 history 63 models 51 modeling 49 more ... police 22 aircrafts 19 military operations 17 aerodynamics of airplanes 9 navy 8 flight control 7 innovation 5 military training 5 aerodynamics 4 construction 4 mechanics of flight 4 first aid 4 simulation and modelling 4 training of personal 4 transport means driving 4 integrated rescue service 3 aeromodelling 3 flight simuators 3 repairs 3 propulsion system 3 investigation services 3 production 3 rescue operations 3 less ...