If other airlines have late deliveries then they either delay the route launch or lease in to cover it. P&O’s new ship Arvia is running late and they’ve cancelled its first cruise and set the date for its new inaugural.
Flybe’s late deliveries result in routes being cancelled outright like this (and others this summer). This is beginning to look like whatever aircraft delays they have are covering for commercial decisions not to go ahead with a particular route or routes. With more route launches to come, you wonder how many more aircraft delivery delays there might be.