Hyperloop is a proposed high-speed transportation system for both passengers and freight. The concept was published by entrepreneur Elon Musk in a 2013 white paper, where the hyperloop was described as a transportation system using capsules supported by an air-bearing surface within a low-pressure tube. Hyperloop systems have three essential elements: tubes, pods, and terminals. The tube is a large, sealed low-pressure system (typically a long tunnel). The pod is a coach at atmospheric pressure that experiences low air resistance or friction inside the tube using magnetic propulsion (in the initial design, augmented by a ducted fan). The terminal handles pod arrivals and departures. The hyperloop, in the form proposed by Musk, differs from other vactrains by relying on residual air pressure inside the tube to provide lift from aerofoils and propulsion by fans; however, many subsequent variants using the name "hyperloop" have remained relatively close to the core principles of vactrains.

Hyperloop was teased by Elon Musk at a 2012 speaking event, and described as a "fifth mode of transport". Musk released details of an alpha-version in a white paper on 22 August 2013, in which the hyperloop design incorporated reduced-pressure tubes with pressurized capsules riding on air bearings driven by linear induction motors and axial compressors. The white paper showed an example hyperloop route running from the Los Angeles region to the San Francisco Bay Area, roughly following the Interstate 5 corridor.