Seeing Lord Brahmā present before him in the sky, carried by his swan airplane, Hiraṇyakaśipu was extremely pleased. He immediately fell flat with his head on the ground and began to express his obligation to the lord.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
स निरीक्ष्याम्बरे देवं हंसवाहमवस्थितम् । ननाम शिरसा भूमौ तद्दर्शनमहोत्सवः
sa nirīkṣyāmbare devaṃ haṃsavāhamavasthitam | nanāma śirasā bhūmau taddarśanamahotsavaḥ
SB 7.3.24