Question: Japan Airlines Co., Ltd. (JAL), is the flag carrier airline of Japan and the second largest in the country behind All Nippon Airways, JAL group companies include which regional commuter airline with its headquarters in the Terminal Building in Nagoya Airfield and in Toyoyama, Nishikasugai District, Aichi, Japan and its main hub at Nagoya Airfield?
Context: Air Japan Co., Ltd. (株式会社エアージャパン , Kabushiki-gaisha Eā Japan ) is a charter airline based on the grounds of Narita International Airport in Narita, Chiba in Japan.  It operates scheduled services under the ANA brand.  It should not be confused with Air Nippon, another ANA subsidiary, or Japan Airlines (JAL), ANA's competitor.  Its main base is Narita Airport.  It was announced on 2 April 2010 that Air Japan and ANA & JP Express will merge, with Air Japan being the surviving company.  Air Japan uses the All Nippon call sign on all flights except the Seoul Incheon and Narita-Honolulu routes which use the Air Japan call sign. Air Central Co., Ltd. (エアーセントラル株式会社 , Eā Sentoraru Kabushiki-gaisha ) was an airline based in Tokoname, Aichi Prefecture, Japan.  It operated passenger services as All Nippon Airways (ANA) flights from its main base is Chūbu Centrair International Airport near Nagoya.  On October 1, 2010, Air Central, Air Next and Air Nippon Network were merged and rebranded as ANA Wings. All Nippon Airways Co., Ltd. (全日本空輸株式会社 , Zen Nippon Kūyu Kabushiki gaisha ) , also known as Zennikkū (全日空 ) or ANA, is the largest airline in Japan.  Its headquarters are located at Shiodome City Center in the Shiodome area of Minato, Tokyo, Japan.  It operates services to both domestic and international destinations and had more than 20,000 employees as of March 2016.  In May 2010, ANA's total passenger traffic was up year-on-year by 7.8%, and its international services grew by 22% to 2.07 million passengers in the first five months of 2010.  ANA's main international hubs are at Narita International Airport outside Tokyo and Kansai International Airport outside Osaka.  Its main domestic hubs are at Tokyo International Airport (Haneda), Osaka International Airport (Itami), Chūbu Centrair International Airport (near Nagoya), and New Chitose Airport (near Sapporo). Okura Nikko Hotel Management Co., Ltd. (formerly JAL Hotels Company Ltd.) is a Japanese-owned global hotel management firm, majority owned by Okura Hotels since 2010.  The hotel firm's managed properties are marketed under the Hotel JAL City and Nikko Hotels International brands.  From its time as a subsidiary of Japan Airlines (JAL), its headquarters have been located in the JAL Building in Shinagawa, Tokyo, Japan.  In 2010, Japan Airlines sold majority ownership of JAL Hotels to the Okura Hotel chain, which is now the primary shareholder. Nagoya Airfield (名古屋飛行場 , Nagoya Hikōjō ) , also known as Komaki Airport or Nagoya Airport, is an airport which lies within the local government areas of Toyoyama, Komaki, Kasugai and Nagoya in Aichi Prefecture, Japan.  It was an international airport but is now a domestic secondary airport serving Nagoya.  (The current primary civil airport for Nagoya is Chūbu Centrair International Airport in Tokoname.) JAL Express Co., Ltd. (JEX) (株式会社ジャル エクスプレス , Kabushiki-gaisha Jaru Ekusupuresu ) , was an airline with its headquarters at Tokyo International Airport and in Ota-ku, Tokyo, Japan, and its main hub at Tokyo International Airport.  The airline also maintained offices in the Japan Airlines Building in Shinagawa, Tokyo.  Its operations included scheduled and non-scheduled passenger services to eight regional destinations across Japan.  In addition, the airline operated additional 15 destinations in Japan and two destinations in the People's Republic of China on behalf of Japan Airlines, under a wet-lease agreement. Nakanihon Air Service is a general aviation company headquartered in Toyoyama, Nishikasugai District, Aichi Prefecture, Japan, by Nagoya Airfield near Nagoya. J-Air Co., Ltd. (株式会社ジェイエア , Kabushiki-gaisha Jei Ea ) , is a regional commuter airline with its headquarters in the Terminal Building in Nagoya Airfield and in Toyoyama, Nishikasugai District, Aichi, Japan and its main hub at Nagoya Airfield.  J-Air previously had its headquarters in Ōmura, Nagasaki Prefecture.  Its operations include scheduled passenger services to 16 destinations across regional Japan, under Japan Airlines' flight numbers.  The airline has a fleet 19 aircraft, consisting of Bombardier CRJ-200s and Embraer 170s. Harlequin Air Co., Ltd. (ハーレクィンエア , "Hārekuin Ea" ) was an airline with its headquarters on the grounds of Fukuoka Airport in Hakata-ku, Fukuoka, Fukuoka Prefecture, Japan.  It was owned by Japan Airlines (JAL) Domestic and operated domestic passenger services.  It ceased operations in April 2005 due to restructuring of JAL Group. Japan Airlines Co., Ltd. (JAL) (日本航空株式会社 , Nihon Kōkū Kabushiki-gaisha , , OTC Pink: JAPSY) , is the flag carrier airline of Japan and the second largest in the country behind All Nippon Airways.  It is headquartered in Shinagawa, Tokyo, Japan; and its main hubs are Tokyo's Narita International Airport and Tokyo International Airport (Haneda Airport), as well as Osaka's Kansai International Airport and Osaka International Airport.  JAL group companies include Japan Airlines, J-Air, JAL Express, Japan Air Commuter, Japan Transocean Air and Ryukyu Air Commuter for domestic feeder services; and JAL Cargo for cargo and mail services.
Answer: J-Air Co., Ltd.