An electronic device may have an elongated sensing strip. Control circuitry may use the sensing strip to gather air gesture input from the fingers or other body part of a user. The electronic device may have a housing. The housing may have portions such as upper and lower portions that rotate relative to each other about an axis. A hinge may be used to couple the upper and lower portions together. The sensing strip may extend parallel to the axis and may be located on the lower portion between keys on the lower portion and the axis or on the upper portion between the edge of a display in the upper portion and the axis. The sensing strip may have a one-dimensional array of sensor elements such as capacitive sensor elements, optical sensor elements, ultrasonic sensor elements, or radio-frequency sensor elements.