1. Go to the airport security place.
2. There is a tree right in front of it with a flowerbed around it and a "Golf Cart" (I dont know what they call those) parked next to it.
3. Jump into the flowerbed and go into prone position

When your whole body is it the flowers, in prone, it is VERY hard to see you unless the opponent walks up on top of you.

And the best part is you can see out to shoot anyone coming. Just try to not move so much because if you move they can see you barely, but it is enough for them to be suspicious and they could spray you with the barret... and we all know how frustrating that is!