Most likely not the end neither for Cologne neither Brussels but all the future investments and growth-operations will be done in Leipzig.The east german city will invest in a new 3600 meter runway,and DHL 300 M Euros to create about 7000 jobs.
Brussels has lost DHL due to heavy night-flight restrictions whereas Leipzig offers 24/24- 7/7 operation without any restrictions. Vatry in France never had a chance,since Leipzig offers first class rail and highway infrastructure.
Cologn and Brussels will remain regional hubs.