It's helpful to know that "au-dessus" is not pronounced as three syllables, but only two, i.e., odsy. Maybe the hyphenated word confuses the computerized TTS. Compare also to the word for "below/under/underneath", au-dessous, pronounced odsu.
True, but Brits would say "sea" even if the birds were flying above the Atlantic. I think the only times we tend to say "ocean" are when referring to "the world's oceans" or a specific ocean.