The recommended approach might vary by what you are waiting for.
For example if the plane is a Vehicle that will come to pick up the passengers, then the easiest approach is probably to have a Server with 0 processing time. Entities will flow through it with no delay, but then wait in the outbound transfer node for the Ride requested.
If you want to wait on something more arbitrary you could direct the entity that enters an outbound transfer node to Wait for an event. Then you would have to add some logic to Fire that event (unless it is one that is already automatically fired).
You should post your questions inside the Simio Insider forum where we can post screenshots and examples to provide a more complete answer.
VP Operations, Simio LLC