  Ambient air cushions the impact of drops on solid substrates, an effect
usually revealed by the entrainment of a bubble, trapped as the air squeezed
under the drop drains and liquid-solid contact occurs. The presence of air
becomes evident for impacts on very smooth surfaces, where the gas film can be
sustained, allowing drops to bounce without wetting the substrate. In such a
non-wetting situation, Mandre & Brenner (2012) numerically and theoretically
evidenced that two physical mechanisms can act to prevent contact: surface
tension and non-linear advection. However, the advection dominated regime has
remained hidden in experiments as liquid-solid contact prevents to realize
rebounds at sufficiently large impact velocities. By performing impacts on
superheated surfaces, in the so-called dynamical Leidenfrost regime Tran et al.
(2012), we enable drop rebound at higher impact velocities, allowing us to
reveal this regime. Using high-speed total internal reflection, we measure the
minimal gas film thickness under impacting drops, and provide evidence for the
transition from the surface tension to the non-linear inertia dominated regime.
We rationalise our measurements through scaling relationships derived by
coupling the liquid and gas dynamics, in the presence of evaporation.
