Valmiki Ramayana Sundara Kanda Sarga 1 Shloka 136

वायुसूनुः son of the Windgod, भूयः च further, ऊर्ध्वम् high up, गतिम् path, प्राप्य taking, तं गिरिम् the mountain, अवलोकयन् while looking at, निरालम्बे in a place without any support, विमले pure, cloudless, अम्बरे in the sky, जगाम went.

Rising higher and further up and looking at the mountain (which was going down into the ocean), the son of the Windgod coursed through the cloudless sky unsupported.