Airport safe/steel free footwear refers to footwear made without the use of steel. In order to provide basic support and stability, shoes generally feature a metal plate called a shank, which is located within the sole and right below the arch. Airport safe/steel free shoes replace this steel structure with a composite, non-metal shank that will not trigger metal detectors, yet still offers the same support.
About Ankle Boots:
Ankle boots are any styling of boot where the shaft of the boot ends at the ankle line on the wearer. Ankle boots shaft height will typically measure up to 4 1/2".