The original question specifically asked if the cables would work on Northwest. The only Northwest planes equipped with laptop power ports are the A330s (not yet in service). The 747-400s should also be getting laptop power as the new business class seats are installed, however there won't be any ports in coach. But to answer the question, no the cords will not work on Northwest. Northwest's laptop power ports will be traditional 110 outlets and will not require any sort of adapter - just plug in your normal power cord.