Slot
A slot is a permitted time window for an aircraft to take off or land at a congested airport. At fully coordinated airports such as London Heathrow, Paris Charles de Gaulle, Nice, Ibiza in summer, Tokyo Haneda and the New York area airports, no flight can operate without one, and business aviation slots are usually allocated after the airlines have taken theirs. Slots come with tolerance windows of 15–30 minutes; miss yours and the aircraft may wait hours for the next. Because a charter operator must request slots for a specific aircraft and time, late changes to your departure can cost you the slot, which is why crews push for punctuality at coordinated airports.