Buddhism and Astral Projection

If you mean by this definition:

Astral projection (or astral travel), is a term used in esotericism to describe an intentional out-of-body experience (OBE) that assumes the existence of a soul called an "astral body" that is separate from the physical body and capable of travelling outside it throughout the universe

Then there are only a few verses that can be interpreted as such in the Pali Canon, for example in the Samaññaphala Sutta of the Digha Nikaya:

"With his mind thus concentrated, purified, and bright, unblemished, free from defects, pliant, malleable, steady, and attained to imperturbability, he directs and inclines it to creating a mind-made body. From this body he creates another body, endowed with form, made of the mind, complete in all its parts, not inferior in its faculties. Just as if a man were to draw a reed from its sheath. The thought would occur to him: 'This is the sheath, this is the reed. The sheath is one thing, the reed another, but the reed has been drawn out from the sheath.' Or as if a man were to draw a sword from its scabbard. The thought would occur to him: 'This is the sword, this is the scabbard. The sword is one thing, the scabbard another, but the sword has been drawn out from the scabbard.' Or as if a man were to pull a snake out from its slough. The thought would occur to him: 'This is the snake, this is the slough. The snake is one thing, the slough another, but the snake has been pulled out from the slough.' In the same way — with his mind thus concentrated, purified, and bright, unblemished, free from defects, pliant, malleable, steady, and attained to imperturbability, the monk directs and inclines it to creating a mind-made body. From this body he creates another body, endowed with form, made of the mind, complete in all its parts, not inferior in its faculties.

...

With his mind thus concentrated, purified, and bright, unblemished, free from defects, pliant, malleable, steady, and attained to imperturbability, he directs and inclines it to the modes of supranormal powers. He wields manifold supranormal powers. Having been one he becomes many; having been many he becomes one. He appears. He vanishes. He goes unimpeded through walls, ramparts, and mountains as if through space. He dives in and out of the earth as if it were water. He walks on water without sinking as if it were dry land. Sitting cross-legged he flies through the air like a winged bird. With his hand he touches and strokes even the sun and moon, so mighty and powerful. He exercises influence with his body even as far as the Brahma worlds. Just as a skilled potter or his assistant could craft from well-prepared clay whatever kind of pottery vessel he likes, or as a skilled ivory-carver or his assistant could craft from well-prepared ivory any kind of ivory-work he likes, or as a skilled goldsmith or his assistant could craft from well-prepared gold any kind of gold article he likes; in the same way — with his mind thus concentrated, purified, and bright, unblemished, free from defects, pliant, malleable, steady, and attained to imperturbability — the monk directs and inclines it to the modes of supranormal powers... He exercises influence with his body even as far as the Brahma worlds."

The term used here is translated as "Mind-Made Body" (S. manomaya-kāya, C. yisheng shen 意生身). This text also details supernatural features, such as clairaudience and mind reading. Manomaya-kāya appears in various contexts in the Pali canon, which provide it with different shades of meaning. These are divided into three categories with nine subcategories:

1. Buddhist practice and attainment,
   • the body as part of a path of practice by practitioners bound for arhatship,
   • the body as the post-mortem destiny of disciples who achieve a certain level of attainment,
   • the body in which the Buddha visits the heaven of Brahmā,
   • the form in which the Buddha comes to a disciple to teach him (once),
   • the kind of body of a generous lay person reborn in a certain heaven.
2. cosmology,
   • the form in which certain devas are incarnated in some heavens
   • the form in which certain beings are reincarnated in the early part of a kalpa in various cosmogonic accounts
3. views of other schools
   • one of a range of objects of identification that can be mistaken for a permanent self, in a teaching where the Buddha refutes the notion of such a self,
   • part of one of seven nihilist views refuted by the Buddha in the Brahmajāla Sutta

In Mahayana texts, the term manomaya-kāya is frequently associated with the dharmakāya (Sanskrit: धर्म काय, "truth body" or "reality body", Chinese: 法身; pinyin: Fǎshēn, Tibetan: ཆོས་སྐུ་, Wylie: chos sku, rdzogs sku). This is one of the three bodies (trikāya) of a Buddha in Mahāyāna Buddhism. The dharmakāya constitutes the unmanifested, "inconceivable" (acintya) aspect of a buddha out of which buddhas arise and to which they return after their dissolution. Buddhas are manifestations of the dharmakāya called the nirmāṇakāya, "transformation body"

Note that this is only a short summary to answer your question for textual references that could be interpreted as OBE. These texts are not taken literally by the majority of Buddhist schools. For an in-depth scholarly analysis of the term, I recommend the following studies:

The Meaning of ‘Mind-made Body’ in Buddhist Cosmological and Soteriological systems

Early Buddhist Dhammakāya: Its Philosophical and Soteriological Significance