midnight
`` It is best for us to wait until after dark . The early morning would be ideal time for an aerial attack on the city , when everybody is helpless and asleep . There 's generally a fog over the river and harbor , too , before sunrise at this season of the year , and that might help them to mask their movements . It would take an aeroplane less than an hour to reach the city from here , so that there is no likelihood of their starting until long after midnight . That gives us plenty of time , and besides we must wait until the Hoffs arrive . '' `` That will make two more -- sixteen of them against our nine , '' warned Dean . `` We can not help it how many of them there are , '' said Fleck .