Bob
To expand on Jim's comment.
There is a fueling / battery loading box where you get ready and then move forward to the start box, when the marshals indicate that a slot is free, we normally allow 5 in the air at a time, you start/arm and then take off to join the current pilots.
If anyone wants to fly with similar models, i.e last year i was in the queue and Richard Ginger went up with his warbird, my self and a few others had warbirds so we joined him and the 3D pilots waited and then flew when we had landed, and vice versa.
This means you can fly with others of a similar ability/ style and enjoy the day.