If the word wingsuit does not ring any bells, how about the Transformers 3 scene of men flying between skyscrapers in Chicago like flying squirrels?

A wingsuit, also known as a birdman suit or bat suit, adds surface area to the body and increases lift. Most wingsuit designs create a surface area between the legs and under the arms.

There are about 600 wingsuiters around the world. They wear parachute equipment designed for skydiving, or BASE jumping, which stands for Building, Antenna, Span (bridges) and Earth (cliffs) - all objects to jump from at high altitudes.

The flier deploys the parachute at a planned altitude and unzips the arm wings, if necessary.

To be a professional wingsuiter first requires practice skydiving and BASE jumping.

The United States Parachute Association stipulates in its Skydivers Information Manual that, before wingsuiting, a minimum of 200 freefall skydives should be made within 18 months and the individual should have one-on-one instruction from an experienced wingsuiter - either that or 500 dives, without an instructor.