Superhydrophobic surfaces are often seen as frictionless materials, on which water is highly mobile. Understanding the nature of friction for such water-repellent systems is central to further minimize resistance to motion and energy loss in applications. For slowly moving drops, contact-line friction has been generally considered dominant on slippery superhydrophobic surfaces. Here, we show that this general rule applies only at very low speed. Using a micropipette force sensor in an oscillating mode, we measure the friction of water drops approaching or even equaling zero contact-line friction. We evidence that dissipation then mainly stems from the viscous shearing of the air film (plastron) trapped under the liquid. Because this force is velocity dependent, it can become a serious drag on surfaces that look highly slippery from quasi-static tests. The plastron thickness is found to be the key parameter that enables the control of this special friction, which is useful information for designing the next generation of ultraslippery water-repellent coatings. Drops moving on liquid-repellent surfaces is a common phenomenon in everyday life, with water pearls running down plant leaves ( 1) or across hot frying pans ( 2). Understanding the many different frictions ( Fig. 1A) opposing motion in these systems ( 3– 11) is important for improving the quality and usability of a wide range of liquid-repellent coatings ( 12, 13). At low drop speeds ( V ≲ 1   mm / s ), at which velocity-dependent resistances are all expected to vanish, water drops (of surface tension γ, density ρ, and viscosity η) are still impeded by the contact-line friction force F μ ≈ 2 l γ ( cos θ r e c - cos θ a d v ) ( 5, 7, 9, 14– 17), where l is the contact area radius, and θ r e c and θ a d v are the receding and advancing contact angles ( SI Appendix, Fig. S1). For a drop with radius R ≈ 1 mm, both the capillary number Ca = η V / γ and the Weber number W e = ρ V 2 R / γ are smaller than 10 - 5 , implying that drops keep a quasi-static shape with contact size l independent of V, despite the motion.