Question: Which is closer to Carlsbad, Phoenix Sky Harbor International Airport and McClellan–Palomar Airport?
Context: The PHX Sky Train is a free, 24-hour electric people mover at Phoenix Sky Harbor International Airport in Phoenix, Arizona.  The first segment opened to the public on April 8, 2013.  The second segment, extending the train to Terminal 3 (with a walkway to Terminal 2) opened on December 8, 2014 State Route 153, also known as SR 153 and the Sky Harbor Expressway, is a former state highway in Maricopa County, in the U.S. state of Arizona, that ran from the intersection of 44th Street and Washington Street in Phoenix south to University Drive.  It was a controlled access arterial expressway, with a speed limit of 45 mi/h , lower than the standard freeway speed of 65 mi/h .  Route 153 was a north–south route that skirted the eastern edge of Sky Harbor International Airport, and along with SR 143, SR 153 served a portion of East Valley residents with access to the airport.  Many motorists used SR 143 (the Hohokam Expressway) instead, because of its quick access to and from Interstate 10 and Loop 202.  The freeway did, however, provide a direct link to office developments in the Southbank commercial project in east Phoenix with the city of Tempe. Phoenix Deer Valley Airport (IATA: DVT, ICAO: KDVT, FAA LID: DVT) is a public airport 17 mi north of Phoenix, in Maricopa County, Arizona.  It is owned by the City of Phoenix.  The FAA's National Plan of Integrated Airport Systems for 2009–2013 categorized it as a "reliever airport" for Phoenix Sky Harbor International Airport. Phoenix–Mesa Gateway Airport (IATA: AZA, ICAO: KIWA, FAA LID: IWA) , formerly Williams Gateway Airport (1994–2008) and Williams Air Force Base (1941–1993), is in the southeastern area of Mesa, Arizona, and 20 mi southeast of Phoenix, in Maricopa County, Arizona.  The airport is owned and operated by the Phoenix–Mesa Gateway Airport Authority, and is a reliever airport for Phoenix Sky Harbor International Airport.  It is a base for Allegiant Air.  The airport authority is governed by a six-member board: the mayors and tribal governor of the town of Gilbert, city of Mesa, town of Queen Creek, Gila River Indian Community, city of Phoenix, and the city of Apache Junction. Phoenix Sky Harbor International Airport (IATA: PHX, ICAO: KPHX, FAA LID: PHX) is a civil-military public airport 3 mi southeast of downtown Phoenix, in Maricopa County, Arizona, United States.  It is Arizona's largest and busiest airport, and among the largest commercial airports in the United States.  PHX covers 3,400 acres (1,376 ha). McClellan–Palomar Airport (Palomar Airport) (IATA: CLD, ICAO: KCRQ, FAA LID: CRQ) is a public airport three miles (5 km) southeast of Carlsbad in San Diego County, California.  It is owned by the County of San Diego.  The airport is used for both general aviation and commercial aviation.  In March 2013 the airport was the fourth-busiest single runway airport in the United States.  In August 2017, the airport announced a new commercial airline Cal Jet, would start operating flights in September 2017. Golden Gate Barrio was a historic Mexican-American neighborhood in South Phoenix, Arizona.  The neighborhood was razed due to eminent domain for the expansion of Phoenix Sky Harbor International Airport in the 1970s and 1980s through the West Approach Land Acquisition Project. Goldwater Air National Guard Base, formerly Sky Harbor Air National Guard Base, is a facility of the United States Air National Guard that exists adjacent to Phoenix Sky Harbor International Airport.  It was built as the result of a 99-year lease in 1949, and was rebuilt in the 1990s to accommodate the creation of a third runway at the airport. Tucson International Airport (IATA: TUS, ICAO: KTUS, FAA LID: TUS) is a public joint civil-military airport owned by the City of Tucson 8 mi south of downtown Tucson, in Pima County, Arizona.  It is the second busiest airport in Arizona, after Phoenix Sky Harbor International Airport. Southwest Airlines Flight 812 (SWA812, WN812) was a passenger flight which suffered rapid depressurization at 34400 ft near Yuma, Arizona, leading to an emergency landing at Yuma International Airport, on April 1, 2011.  The incident caused minor injuries to two of the 123 aboard.  The aircraft involved, a Boeing 737–300, was operating Southwest Airlines' domestic scheduled service from Phoenix Sky Harbor International Airport, Phoenix, Arizona, to Sacramento International Airport, Sacramento, California.
Answer: McClellan–Palomar Airport