Originally Posted by Thunderroad

SG, thanks for this very valuable suggestion. I'd been vaguely aware of the ITA Matrix, but hadn't used it before.

However, one does seem to need to work it a bit differently than you'd described or at least the way I'd interpreted what you'd described. Rather than plugging in ":: aa+" following the origin and destination airports on the same lines, what seems to work is click on "advanced routing codes" and plug in "aa+" there.

Regardless, thanks again.