How did the black people help in World War 1 and World War 2?

African Americans were assigned to mostly transportation and supply details. There was one African American flying squadron that escorted B-17's into Germany. They flew Mustangs and were very sucessful at protecting the B-17's. I don't believe they lost a single bomber while in their care. I'm sure there are other examples of African American fighting units but it was not the norm at that time.