When performing the head-tilt chin-lift technique how do you straighten windpipe to allow air movement in and out of lungs?

You do not straighten the windpipe when performing the head-tilt chin-lift technique. Straightening the windpipe is a separate move called the jaw-thrust technique. Instead, when doing the head-tilt chin-lift, all you should do is extend the neck by tilting the head back while bringing the chin upwards until the patient reaches a neutral position with their head slightly flexed.