Good catch - thanks. I just relied on MileageMonkey to do a quick check of the validity, rather than actually checking flights.

That said, I think using that would be very risky. It relies on AA not changing the flight number - not something I would want to be relying on, given the current environment, reduced and/or changing service etc. AA tends to change some of the flight numbers every now and again anyway. Relying on STL-MIA and MIA-SXM to have the same flight number a year from now is not a bet I'd particularly want to make.