From memory the Norwegian take over was attractive for IAG largely due to the latters much lower cost of capital. As alluded to above many LH routes would have been culled and aircraft would be transferred across the IAG group. Norwegian also had an attractive order book for aircraft. Once you refinanced the debt/offloaded it then Norwegian had a much lower cost base than some of the IAG opcos and would have been a good fit in the loco segment.