The Infamous Lost Pan Am Flight 914 Finally Lands, 30 Years Later

Happenstance

This could just be a wild coincidence, and statistically speaking, more planes successfully fly through the Bermuda Triangle than ones that disappear.

Aliens

Definitely the most believable on the list, a lot of theorists believe that the Bermuda Triangle is frequently visited by little green men. Take this one with a grain of salt, or three.