Boeing on Tuesday intensified its counter-attack against Airbus by approving the launch of a stretched version of its 747 jumbo as a belated rival to the Airbus A380 super jumbo, the world’s largest passenger aircraft.

The 747-8 is being introduced initially as a freighter aircraft on the strength of 18 firm launch orders from two all-cargo airlines Cargolux of Luxembourg and Japan’s Nippon Cargo Airlines, which will both take delivery of their first aircraft in the second half of 2009.