So how the hell are the White Walkers supposed to be a threat now that Jon and Dany seem to have a pretty strong alliance and she has three fire-breathing dragons?
Dany could just fly around in circles for a couple of hours and reduce every wight to ash, and then they could send in 1,000 dudes with dragonglass/Valryian Steel weapons to cut down the White Walkers.
I know that we have to get to that point in the plot, but if it happened right now, the WWs wouldn't stand a chance. It's not like they have archers or anything that can even hurt giant flying dragons.