The flight was held for connections.

A hold, however, is not open-ended. A connection hold is an authorization for the gate agent to delay the close of the boarding door by a set number of minutes. That allows extra time for connecting passengers to make the flight but doesn't guarantee everyone will make it.

The amount of time that the boarding door closure will be delayed is based on data including flight plan time, crew legalities, aircraft's next flight, arrival gate availability, curfews, slot restrictions, and onward connections. The program is able to bring together much more data than an operations agent would have been able to access in the past and it recommends a hold time that allows more connections to be made without causing other problems downline.