From the Executive Summary: "Human trafficking is a form of modern day slavery that involves the use of force, fraud, or coercion to obtain labor or a commercial sex act; and the commercial sexual exploitation of children under any circumstances. Globally, it is estimated that as many as 24.9 million men, women, and children are exploited in various forms of contemporary slave-like practices. Human trafficking flourishes as a business as a result of the lucrative profits it generates--approximately $150 billion annually worldwide. The pervasiveness and profitability of human trafficking raises daunting challenges for the transportation industry, as the use of transportation and transportation networks figures prominently in human trafficking enterprises within the United States and internationally. Traffickers often rely on the transportation industry in every phase of human trafficking: for recruitment, moving and controlling victims, and for delivering victims to buyers who will complete their exploitation through either commercial sex or forced labor ventures. The limited transportation-related human trafficking data available in the U.S. confirms that victims are being trafficked by airplanes, buses, subways, trains, taxis, rideshares, cruise ships, and private vehicles."
U.S. Department of Transportation: https://www.transportation.gov/