A pilot recently asked me what the alternating white and black stripes were on the carrier ramp of her airport. I’m sure a lot of people are curious, so I’ll share the answer here. It is called the zipper line and it extends across many carrier and cargo ramps prior to the movement area. It is called a zipper line because it resembles a zipper, very simple. It is a marking that pilots do not need to recognize because it is for use by airport tenants. It is used at many major airports throughout the United States and is simply a boundary for vehicles, which keeps vehicles and employees far enough from the movement area so that no accidental crossings are made. This is not an FAA (Federal Aviation Administration) marking, thus many airports may use slightly different variations, but its purpose is the same.