The Hyperloop concept is proposed to operate by sending specially designed "capsules" or "pods" through a continuous steel tube maintained at a partial vacuum. Each capsule floats on a 0.5-to-1.3-millimetre (0.02 to 0.05 in) layer of air provided under pressure to air-bearing "skis", similar to how pucks are suspended in an air hockey table, thus avoiding the use of maglev while still allowing for speeds that wheels cannot sustain. Linear induction motors located along the tube would accelerate and decelerate the capsule to the appropriate speed for each section of the tube route. With rolling resistance eliminated and air resistance greatly reduced, the capsules are theorized to be able to glide for the bulk of the journey. In the Hyperloop concept, an electrically driven inlet fan and air compressor would be placed at the nose of the capsule in order to "actively transfer high pressure air from the front to the rear of the vessel," resolving the problem of high speed transport in a tube that is not a hard vacuum, wherein pressure builds up in front of the vehicle, slowing it down.[2] A fraction of the air is shunted to the skis for additional air pressure, augmenting that gain passively from lift due to their shape.
In the alpha-level concept, passenger-only pods are to be 2.23 metres (7 ft 4 in) in diameter[2] and projected to reach a top speed of 760 mph (1,220 km/h) so as to maintain aerodynamic efficiency;[citation needed] the design proposes passengers experience a maximum inertial acceleration of 0.5 g, about 2 or 3 times that of a commercial airliner on takeoff and landing. At those speeds there would not be a sonic boom; with low-pressure warm air inside the tubes, Musk hypothesizes the pods could travel at high speeds without exceeding Mach 1.[23]