Yes they do, but two people sitting outside together doesnt neccesarily imply anything. Now dont get me wrong, I feel Cloud and Tifa get together as well, but the Highwind scene doesnt neccesarily clinch it because it varies.

And when it comes right down to it, regardless of how the feel for eachother, Cloud and Tifa are all eachother has outside the party. Cloud had nowhere to go; no hometown, no family, and Tifa was the same. No hometown, no family, no bar, no nothing. So the two of them sitting outside the Highwind isnt really a deciding factor in the two of them getting together.

edit: That's to ultimalord. My first sentence sounds like its meant towards Ballistix, it aint.