Parasite Drag
All parts of the aircraft experience some air resistance in flight and the faster we fly, the more resistance there is. This is known as parasite drag.
Imagine you are on a bike – the faster you ride the more resistance you encounter. If you lean your body forwards to make yourself more streamlined, the resistance reduces because you have reduced your parasite drag. Similarly, the aircraft designer makes the components as streamlined as possible to reduce parasite drag.
Some aircraft have more advanced features to reduce parasite drag, such as a retractable undercarriage.
Parasite Drag and Airspeed
Once configured in level cruise flight, the pilot can only alter parasite drag by changing airspeed. The faster the airspeed, the higher the parasite drag.
The diagram here shows how both parasite drag and induced drag vary with airspeed in level flight.
