SB 4.12.19
sa dadarsa vimanagryam
nabhaso ’vatarad dhruvah
vibhrajayad dasa diso
rakapatim ivoditam
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
As soon as the symptoms of his liberation were manifest, he saw a very beautiful airplane coming down from the sky, as if the brilliant full moon were coming down, illuminating all the ten directions.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
There are different levels of acquired knowledge — direct knowledge, knowledge received from authorities, transcendental knowledge, knowledge beyond the senses, and finally spiritual knowledge. When one surpasses the stage of acquiring knowledge by the descending process, he is immediately situated on the transcendental platform. Dhruva Maharaja, being liberated from the material concept of life, was situated in transcendental knowledge and could perceive the presence of a transcendental airplane which was as brilliant as the full moonlight. This is not possible in the stages of direct or indirect perception of knowledge. Such knowledge is a special favor of the Supreme Personality of Godhead. One can, however, rise to this platform of knowledge by the gradual process of advancing in devotional service, or Krsna consciousness.