Who will be the most impacted by a delayed entry into service of the Boeing NMA?

https://epsilonaviation.wordpress.com/2019/05/05/who-will-be-the-most-impacted-by-a-delayed-entry-into-service-of-the-boeing-nma/

https://leehamnews.com/2019/05/02/max-impact-on-boeing-nma-beginning-to-emerge/