DREAMS
Birds in flight may symbolize freedom from limitation in much the same manner as flying dreams. This ability to fly also makes birds symbolic of the soul set free from the body.

The Language of the Birds

In fact, there exists in mythology something known as "The Language of the Birds" which is a text that contains the original language spoken by humanity. It is said that anyone who can decipher the Language of the Birds will have complete understanding not only of other languages, but of the mysteries of life itself. The Language of the Birds is also known as the Angelic Tongue, supposedly being the language the the angels themselves speak. With such an emphasis on birds' ability to communicate, it seems pretty obvious that a dream bird may represent communication of some form. The bird may be a herald, bringing messages from the soul indicating positive change in waking life.

Spiritual Awakening

The dove is probably the most easily recognizable bird symbol. In waking life, the symbol of the dove is one of peace as well as a symbol of the Holy Spirit. Dreaming of a dove may symbolize feelings of peace or the end of a battle be it mental, spiritual, physical or emotional. She may also symbolize deep spiritual awakening or may herald news from your higher self.

Unconscience

Carl Jung said that birds represent thoughts while birds in flight symbolize moving and changing thoughts. Birds are generally associated with freedom and abandon. Seagulls are seen flying over the ocean and following beach combers who feed them can, in addition to the other typical bird symbolism may also represent the unconscious as they are associated with the sea. An eagle is a powerful bird and the unconscious message may be prosperity, success, and liberation from tedium. The eagle is also a bird of prey and some negative connotations can be made. If the eagle is on the attack or the dream is frightening, it may reflect on your own aggressive thoughts and tendencies.

https://www.bellaonline.com/articles/art13600.asp