To be more precise, Sabena was the very long-standing national airline of Belgium, code SN, and built up a substantial long and short-haul network. In more recent times they developed Delta Air Transport (absolutely no connection with Delta Airlines in the US) as an independent codeshared and co-branded commuter carrier on the US pattern.

There's not as much business at Brussels as airlines think, and after years of government featherbedding, notably rude and idle staff, and frequent strikes (not for nothing was Sabena known as "Such A Beastly Experience Never Again"), SN finally went under, to the surprise of most employees. Delta AT survived and continued the best routes, and have expanded back over quite a bit of the old network under the "SN Brussels" name. They have retained the "SN" part and a lookalike-Sabena livery feeling there was some collateral in the old name. They have also expanded beyond their commuter aircraft (they had a significant fleet of 146 regional jets) to new Airbus main line aircraft, all the former Sabena aircraft, many of which were quite new Airbuses, having been disposed in the meantime (the big fleet renewal contributing to Sabena's financial woes).