The state troopers are flying a Hiller Model 360 when first shown searching for the escapee. In their next flying scene, they are flying a Bell 47.
State troopers in the helicopter that's used for searching for Cobbett. On closeup shots of the trooper pilots it can clearly be seen that the helicopter they are supposedly flying in is suspended from a sound stage studio ceiling by heavy duty test wiring, possibly piano wire. It can be seen over the head of the trooper as he communicates over the radio.