OLC = Oak Leaf Cluster

The OLC is worn on the ribbon as a designator of the number of awards.

As I said, he has 8 Oak Leaf Clusters which means he has the basic award of the Air Medal plus 8 additional awards of the Air Medal which are represented by the Oak Leaf Cluster.

There is a Bronze Oak Leaf Cluster that = 1 OLC
There is a Silver Oak Leaf Cluster that = 5 OLC

After the award of the 10th Air Medal the number of OLC's is given numerically, in other words, they put the actual number of additional awards on the ribbon

Dave