What does negative ghostrider the pattern is full mean?

When aircraft are queuing up to land they fly around in some kind of well defined, circular pattern to avoid collisions. There are rules about minimum separation between planes so only so many can fit in the pattern before it's full.

The quote comes from the Movie "Top Gun" after the Tom Cruise character requests permission to fly by the [airfield's control] tower. The callsign for his aircraft was "Ghostrider" so the quote translates to:

No, you may not fly your aircraft past the control tower because there are many other aircraft nearby waiting to land.