Ключевые слова: air, aircraft, airline, airliner, airplane, airport, ban, barrier, border, boundary, cage, chain, commercial, concept, danger, do not enter, fence, flight, forbidden, grid, hole, industrial, industry, iron, jet, landing, mesh, metal, metallic, military, net, plane, politics, prison, protection, safety, security, steel, transport, transportation, wall, wire, wired,