US Airways Dividend Miles (Pre-FlightFund Merger) - seat availability on usair?

Just bought a ticket on usair.com and it showed only one seat remaining on the flight. I selected it and checked flyaow.com for seat avaiable and it showed 9's across the board. Which one is correct? thanks

Likely both. Airlines block seats for Airport use so not all seats show on a seat map, some are also reserved for premium pax and may not show. Airlines also overbook flights so they may show 9 seats to sell and only have 1 physical seat to pre-book. It is likely a mix of factors.