Question: Which expressway connects eastern Beijing with the airport located 32 km northeast of Beijing's city center?
Context: The Nanning–Youyiguan Expressway (), commonly referred to as the "Nanyou Expressway" (), is a 225.06 km in the Chinese autonomous region of Guangxi that connects the city of Nanning, the capital of Guangxi, and Friendship Pass, known in Chinese as "Youyiguan", a border crossing between China and Vietnam.  The Friendship Pass is located in the county-level city of Pingxiang, under the administration of the city of Chongzuo.  At the border, the expressway connects with National Route 1A in Vietnam.  The expressway is designated G7211, and opened on 28 December 2005. The Kuala Lumpur–Kuala Selangor Expressway (Malay: Lebuhraya Kuala Lumpur–Kuala Selangor), KLS "(formerly Ijok–Templer Park Highway (Malay: Lebuhraya Ijok–Taman Templer ), LATAR)" or sometimes called LATAR Expressway (Malay: Lebuhraya LATAR ), is an expressway in Selangor, Malaysia.  It is part of the Kuala Lumpur Outer Ring Road.  The 32 km expressway connects Ijok near Kuala Selangor to Templer's Park near Rawang and not Kuala Lumpur as its name suggests – consequently, motorists will need to travel another 20 km to Kuala Lumpur via Kuala Lumpur–Rawang Highway.  Kuala Lumpur–Kuala Selangor Expressway is the fourth east–west-oriented expressway in the Klang Valley after the Federal Highway, the New Klang Valley Expressway (NKVE) and the Shah Alam Expressway. Beijing Capital International Airport (IATA: PEK, ICAO: ZBAA) is the main international airport serving Beijing.  It is located 32 km northeast of Beijing's city center, in an enclave of Chaoyang District and the surroundings of that enclave in suburban Shunyi District.  The airport is owned and operated by the Beijing Capital International Airport Company Limited, a state-controlled company.  The airport's IATA Airport code, PEK, is based on the city's former romanized name, Peking. North–South Expressway Central Link, NSECL , AH2 , (Malay: Lebuhraya Utara–Selatan Hubungan Tengah ) also known as ELITE or ELITE Expressway "(Expressway Lingkaran Tengah)", is the main expressway in Malaysia.  The 60 km expressway connects Shah Alam Interchange Exit 601 to Nilai North Interchange Exit 612.  This expressway is part of the North South Expressway network and it is a critical link for the North–South Expressway providing northbound and southbound travelers with an uninterrupted journey bypassing the city congestion in Kuala Lumpur.  The expressway is part of the Asian Highway Network of route AH2. Putrajaya–Cyberjaya Expressway, Federal Route 29, is a major expressway in Klang Valley, Malaysia.  It is the first future federal highway on the Multimedia Super Corridor (MSC) area.  The 21.2 km (13.2 mi) expressway connects Serdang interchange on Damansara–Puchong Expressway to Kuala Lumpur International Airport (KLIA) in Sepang.  It was named after the two sides of the MSC cities, Putrajaya and Cyberjaya. The 2nd Airport Expressway (), officially numbered S51, is a toll expressway that connects eastern Beijing with Terminal 3 of Beijing Capital International Airport.  It opened on February 29, 2008, just prior to the 2008 Beijing Olympics.  It runs for 11.5 km from Yaojiayuan Road in Chaoyang District to the terminal. Duta–Ulu Klang Expressway (DUKE), , is the main expressway network in Klang Valley, Malaysia.  The 18 km expressway connects New Klang Valley Expressway's Jalan Duta Interchange E1 to Taman Hillview Interchange on Kuala Lumpur Middle Ring Road 2 28 in Ulu Klang.  The expressway was constructed to provide the "missing link" between New Klang Valley Expressway E1, Kuala Lumpur–Karak Expressway 2, E8, and Kuala Lumpur Middle Ring Road 2 28.  This expressway is also known as the Kuala Lumpur Northeast Dispersal Link Scheme.  It was proposed by Tan Sri Datuk Lim Kang Hoo, a chairman of Ekovest Berhad. The Northern Airport Line, officially numbered S28, is an 11.29 km toll road extension that runs from G45 Daqing–Guangzhou Expressway (formerly Beijing-Chengde Expressway) to the Beijing Capital International Airport in Beijing, China.  It was opened in September 2006.  The opening of this road has helped to alleviate traffic on the Airport Expressway, which had been the sole highway link to the airport.  The Northern Airport Line allows drivers from Zhongguancun and points north and west of the city to head north first on Jingcheng Expressway before going directly east to the airport, instead of having to go east on the 4th Ring Road to get on the Airport Expressway, where traffic is often clogged near the Siyuan Bridge. Pichoy Airport (Spanish: "Aeródromo Pichoy" ) (IATA: SCVD) is an airport located 32 km northeast of Valdivia, a city in the Los Ríos Region of Chile. The Johor Bahru Eastern Dispersal Link Expressway, EDL (also known as Johor Bahru Eastern Dispersal Scheme) AH2 (Malay: Lebuhraya Penyebaran Timur Johor Bahru), is an expressway in Johor Bahru, Johor, Malaysia.  The 8.1 km expressway connects the end of North–South Expressway Southern Route at Pandan to the new Sultan Iskandar Building CIQ Complex in the city centre.  It is a toll free expressway and act as bypass to CIQ complex without using Tebrau Highway (Federal Route 3) to the city centre.  This project is part of the JB Master Plan and is linked with the Iskandar Malaysia project "(formerly South Johor Economic Region (SJER) or Iskandar Development Region (IDR))" to propel the region into a modern economic powerhouse.  The construction costs of the expressway is RM 1 billion.
Answer: The 2nd Airport Expressway