Expanding UAE as "Unidentified Anomalous Phenomena" covers both cases; change the A to "Aquatic" or "Aerial" to taste, without breaking the acronym. (Info from the UFO page on Wikipedia, which helpfully adds "Not to be confused with Unidentified Submerged Object", but fails to mention United Arab Emirates.)

I still get odd looks when I say that air is a fluid. ("Not to be confused with liquid", quoth Wikipedia, so ner.)