Flying ants are the reproductive males and females of the common Black Garden Ant. They will only be seen flying for a few days in July or August when they seek a mate. The mating takes place in the air and the female will then find a suitable nest site for the winter. In spring she will begin to lay eggs and start up a new colony.
If you are worried about flying ants, rest assured it will not last for long. However, if you experience an ant invasion in your home or place of work, professional help is recommended.