Earlier today, Twitter lit up with a report that flights into NYC’s LaGuardia airport had been halted by the FAA due to a shortage of air traffic controllers affected by the government shutdown. LaGuardia is one of the busiest in the country, serving roughly 30 million passengers a year as of 2016, which makes the prospect of it sitting idle on a Friday particularly scary. The reality of the situation, however, is that the FAA ultimately placed the airport on what it calls a Ground Delay Program, which helps keeps planes safe in the air, but can have serious ripple effects for travelers trying to take to the skies. That reportedly came after a full ground stop, which it needed to get the schedules in order. Here’s how these intentional stops and delays hope to cut down on unexpected scheduling scrambles.