OVA series, and quite watchable even if you have no idea what the background is - everything you need is introduced.
Very dialogue free, and with a lot of music (well, two of the main characters are singers, and there are some VERY strange things in the background about music saving the earth - literally)
The brief dialogue between the two pilots at the end of the first episode is, perhaps, the most wonderful two sentences in a film ever. The whole film has been leading up to it.