Originally Posted by NickB

Just wanted to add that there appears to be caselaw before the ECJ (WZ v Austrian Airlines) to confirm the view that, in case of re-routing to an alternate airport, the relevant time is the time of arrival at the original scheduled destination rather than the alternate airport (or ultimate alternative end destination specified by the passenger) airport including ground transfer time. So, if you are rerouted from EWR to JFK, arrival time will have to take into account the time to transfer from JFK to EWR (or, if the passenger is going to, say, Manhattan, the time to transfer to the passenger destination in Manhattan).