As per Manticore's link, it looks like the film is Phoenix 2772, a 1980 science fiction animation from Japan, written by Osamu Tezuka:
Phoenix 2772 is set in the distant future where the planet Earth is dying from a lack of energy resources and a disheartening political climate sees all human beings produced by computers to live out certain social roles, the colour of the eyes determining the baby's rank, from pilot to politician, etc. Godo is one such child brought up to be a cadet and nursed by the beautiful robot-maid Olga. After noticing his exceptional abilities, Rock, a dictatorial candidate for prime minister, selects Godo to fulfil his agenda and travel into deep space and capture the mystical Phoenix, its blood will manifestly heal the Earth (and selfishly make Rock prime minister). This eventually proves hard for Godo for many reasons, partly because he has a love of all living creatures and he detests his being trained for what appears to be that of a ruthless hunter. He is also to leave his one friend in his adolescence, Olga, to deletion. Most importantly he elopes with Rena, a "daughter of the elite" and bride-to-be of Rock when it is forbidden for his rank to communicate with such a woman.
While Gado's robot maid, Olga, is pretty human, the phoenix may be what you're thinking of. It has some trailing peacock-like feathers which do look sort of trumpet-like, and are purple in the episode, albeit orangeish on the VHS box cover:
Although there are a fair number of other aliens that show up:
Here is a trailer: