The Collaborative International Dictionary of English v.0.48:

landing strip \land"ing strip`\, n. (Aeronautics)
   A runway at an airport, at which airplanes land[3]; the long
   smooth surface used for takeoff or landing[4].
   [PJC]

WordNet (r) 3.0 (2006):

landing strip
    n 1: an airfield without normal airport facilities [syn:
         airstrip, flight strip, landing strip, strip]