This rather amazing video shows what 24 hours looks like to the Air Traffic Controllers Around the world.
That is A LOT of planes. but this animation actually involves some explanation, and makes it clear just how crowded our airspace can get.
So why is having a few ATC controllers furloughed a big deal? Well the simplest answer is the system is already overworked as it is. I would invite you to go watch United 93. The sheer chaos and confusion seen in the film as ATC operators try to grapple with a dynamic and escalating crisis makes it clear that they had little or no control over the situation. There was actually a dramatic moment on September 11th were American 11 almost hit United 175. Even if we were to proportionately lower the number of flights, the ATC system is still overworked as it is.
The good news is that even if the controllers are completely missing their screens, even if two planes are headed right towards each other in level flight, at altitude, there is a nifty devise called TCAS that will allow them to avoid each other. It basically works with the radar in the plane and the transponders of the surrounding airplanes to give out a warning and an urgent command to any pilots that might be in danger of a collision. The rather unfortunate bit about this is that not all planes have this system. If say a Cessna were to stray into the flight path of say a 727, then no one would really have a clue until it were too late. ATC is the last line of defense, to warn the pilots of the danger.
But there's another thing that happens that has nothing to do with terrorists, and it has the potential to be lethal to a great number of passengers. That threat is called runway incursion. Runway incursion is simply a plane being on a runway that isn't supposed to be there. There have been numerous accidents involved with runway incursion. So many in fact, that it is considered the #1 cause of all air traffic accidents. The deadliest crash in aviation history occurred because of runway incursion. The scariest thing about runway incursions is that just like runway over runs, the number of incidents are increasing as the use of air travel has become essential to our economy.
The political calculations that lead anyone to think the sequester was a good idea have all been proven to be null and void. The political calculation to make it hurt as much as possible should well be taken with care. Politics has no place in public safety. Reguardless of who said what, or when the bright idea was had to cut the number of ATC's on duty, the end result aside from the delays is a potentially fatal situation where and already overworked system is not being manned by enough eyes and someone makes an all too human mistake. It has happened before, it most likely will happen again. The question is how much will it hurt?