Sometimes I feel like a scientist walking around a plane wearing a white coverall top with rubber gloves as the hot gases from the Turbine is mixing with the cold air outside, and the smell of mixture of metal, probably inconel and jet fuel while the turbine cowling is popping and making crackling noises from the heat meeting up with cold air after engine shut down. It's cold outside, but you run into a pocket of warm air just behind the engine or right behind the hot brakes, a temporary relief from the cold wind outside. Just that most of the passengers have no clue the amount of thinking and technology that has gone into aviation. Like what keeps a plane warm inside? It's not like a heater in your car. But in a way it is. It's coming from the engine and the warm air coming into the inside of the cabin comes from the engine bleed air. In a car, warm air is transferred into your car by coolant going through your heater core.