Ronald Reagan Washington National Airport (DCA).Newark Liberty International Airport (EWR).In the U.S., there are four airports with FAA slot controls: Without slots, the thinking goes, these airports would be so congested that it would be very difficult for flights to operate without delays. They exist at airports that the Federal Aviation Administration (FAA) deems capacity constrained. What is a slot?Ī slot is the authorization for a flight to use a runway at a busy airport for either a takeoff or a landing. However, slots are in use at numerous busy airports around the world, and the basic reasoning for slots globally is generally the same as it is in the U.S. Since the slot process differs by country, we'll focus on how slots work in the U.S. Well, we're here to help you understand the basics on what an airport slot is - and how the process works. But maybe you've wondered what exactly is a slot, and how does one work? And why, during the COVID-19 pandemic, are airlines 'squatting' on these slots? If you're a regular TPG reader, you've probably heard about slots before.