Sorry have never understood the need for landing slots.
Most pilots are good at planning aproach (or are we saying that the current training regimes just don't turn em out as well as they used to what with radio not eyes being the main aid).
Landing slots by their very nature place pressures on pilots which need not be there.
I enjoy flyins with like minded folk, some entertainment if overnight is on offer and the ability to take in movements at one's ease with perhaps some good basic and food and facilities