There's this stray hokum helicopter in the Highway 101 team deathmatch map. I and other people recently noticed it. I noticed it while playing on two different servers too. The hokum is located behind the blue base towards the southwest (from blue base, take heading 230). It appears to be on the red team; it will attack blue players.
It's funny, I wonder if it was always there and people are just finding out about it now.