> There can be two Skycams in major playoff games or the Super Bowl (high and low).

There can be more depending on how you block out the cables, I have seen 5. The two Skycam limit is based on two independent systems that do not do cable avoidance in software, you just block out the allowed altitudes on each system.

There also other cable suspended systems in use to move on a line strung between two points and sometimes a track suspended under the stadium roof.

Fun fact: The Skycam was invented by Steadicam inventor Garret Brown and uses some of the same principals for stabilization.