Nashville is a big weekend destination, especially this time of year with music festivals, college graduations, etc. Downtown and midtown hotels are always booked up months in advance on weekends. Airport hotels fluctuate on weekends depending upon the time of year. We are going into the busiest time. The majority of the new hotels are being built downtown, and not much capacity is being added to the airport area, so things are tight. You might want to look at suburbs to the south or east of the city (Brentwood or Mt Juliet) if you have a car and can't find much close to the airport as they are only 15-20 minutes away on the weekend.