In this question I asked about the pilot's ability to give a signal to others nearby while on the ground. My question here is, if someone else wants to get the pilot's attention on the ground, could the pilot hear someone honking a car horn from the cockpit?
Edit: thanks for all comments. I want to ask about a situation involved large aircraft, engine running, car is near the aircraft. Such as in large airport operation. My question comes from series Ultimate Airport: Dubai when a trainee is driven to different areas of airport as part of his certification. I wonder if he can call attention of pilot in cockpit by honking the horn. I am aware that more standard mode of communication such as radio, flare or ground marshall is preferable.