From the Cathecism of the Catholic Church:
CCC 328 The existence of the spiritual, non-corporeal beings that
Sacred Scripture usually calls "angels" is a truth of faith. The
witness of Scripture is as clear as the unanimity of Tradition.
CCC 329 St. Augustine says: "'Angel' is the name of their office, not
of their nature. If you seek the name of their nature, it is 'spirit';
if you seek the name of their office, it is 'angel': from what they
are, 'spirit', from what they do, 'angel.'" With their whole beings
the angels are servants and messengers of God. Because they "always
behold the face of my Father who is in heaven" they are the "mighty
ones who do his word, hearkening to the voice of his word".
CCC 330 As purely spiritual creatures angels have intelligence and
will: they are personal and immortal creatures, surpassing in
perfection all visible creatures, as the splendor of their glory bears
It should be noted that the ability for people to interact and see angels constitutes a miracle. Being a miracle, one cannot produce conclusions of the angelic nature from such events.