When was the last time American ground forces were attacked by enemy air craft?

I've been trying to find this out for quite a while, and even my USAF friends don't know. Some speculate that it was towards the end of WW2, others thought there might have been a strafing attack or two in the Korean war. I know there was a small amount of air to air combat during Desert Storm, but I don't think there was air to ground.

NOTE: NOT Talking about missile strikes, but an actual strafing or bombing by an enemy aircraft.