and D's security checkpoint into 11 lanes which, if necessary, can be expanded to 16 lanes. Other features include a dedicated drop-off area for carry-on-only passengers, biometric scanning technology, a sensory room designed for those with autism, and Delta's largest Sky Club to date. As of June 2022, Delta is in the process of replacing Terminal D's gates and will start construction of Concourse D. Delta is fast-tracking its remaining projects at Terminal C due to the impacts from the COVID-19 pandemic, which allowed the airline to use the decrease in passage traffic to speed up construction by two years. Operations While LaGuardia frequently accommodates general aviation, the airport is primarily serviced by Part 121 scheduled air carriers providing passenger service to regional, domestic, and limited international destinations. Because of its congested nature and proximity to dense urban neighborhoods, commercial flights to and from the airport are subject to several restrictions enacted by both the Federal Aviation Administration (FAA) and the Port Authority of New York and New Jersey (PANYNJ). The airport almost only ever handles narrow-body aircraft and can handle Airplane Design Group (ADG) IV widebody aircraft such as the Boeing 767 and the Airbus A310, however, these aircraft in this group are rarely seen at LaGuardia. Service restrictions International flights The airport does not have U.S. Customs and Border Protection (CBP) facilities. As such, international arrivals are only possible from airports serviced by United States border preclearance. Passengers and crewmembers on these flights clear customs at their departure airport and—for immigration purposes—are considered to be on the US territory during their entire journey, allowing them to exit LaGuardia in the same manner as domestic travelers. Curfew and Perimeter Rule To mitigate the impact of aircraft noise pollution and facilitate airfield maintenance, a seasonal curfew traditionally exists between the hours of 12am and 6am during the warm months of the year. Additionally, a 1984 "Perimeter Rule" implemented by PANYNJ bars airline flights to and from points farther than , except on Saturdays or to Denver, Colorado. With long haul operations generally requiring heavier fuel loads and larger aircraft, the regulation aims to eliminate excess perceived noise generated by such flights. Changes to the Perimeter Rule were considered as recently as 2015, but a New York State Senate bill was introduced in 2021 with the intent of codifying the rule into law. Slot system As one of the United States'