" British Airways lists flights that are the second-lowest price as the lowest,"

That sentence makes it sound like they deliberately always put the 2nd lowest price as the lowest every time. It was pretty misleading or poorly written.

See http://darkpatterns.org/british-airways-distract-from-cheape....

I think that's still really stretching. "In fact, it's only the lowest price in that ticket class".

If I saw those boxes across the board, like in their example image, it doesn't take a second thought, it's "obvious" (to me anyway), that those are the "lowest, per class".

Yeah, that's why I described it as an examples of a bad design choice that may be accidental rather than a dark pattern. I do still think it's misleading, though.