Why do planets not twinkle?
The twinkling is not from the stars but is due to disturbances in the air.
Stars are too far away, so we can not see the disk of the star. What we get instead is the point source of light... planets are near bye comparison to stars and we actually see their disk or body. The light beam bends in the atmospheric hot air layers, but the planet's image is larger and can create good image.