The Air France-KLM group said it purchased 19.9% of Stockholm-based SAS on Wednesday and will begin an extensive commercial cooperation with the Scandinavian airline on Sunday. Air France-KLM said the operation follows the receipt of regulatory approvals in Europe and the United States. As announced earlier, Air France-KLM and SAS have signed far-reaching interline and codeshare agreements to connect their hubs and networks. These agreements, which cover reciprocal loyalty program benefits, will enter into force as early as Sunday. That is when SAS will join the Skyteam alliance, of which Air …