An underground hangar complex may include tunnels containing the normal elements of a military airbase - fuel storage, weapon storage, rooms for maintaining the aircraft systems, a communications centre, briefing rooms, kitchen, dining rooms, sleeping areas and generators for electrical power.
Countries that have used underground hangars include Albania, China, India, Italy, North Korea, Norway, Sweden, Switzerland, Taiwan, Vietnam and Yugoslavia.
By country 
The Indian Air Force operates underground hangars. Sukhoi Su-30 MKI have been stationed at Trishul Air-base situated in Bareilly, Uttar Pradesh, India. It houses one of the largest underground hangars in Asia. Adampur, situated in Punjab, houses an air-base with underground hangars. It is the home base for MiG-29 and MiG-21 interceptors.
The largest underground hangar complex in former Yugoslavia was at Željava Airport near Bihać, with enough space for 80 MiG-21s. Slatina Air Base, located at Pristina International Airport, contained the second largest.
The only Taiwanese airbase where has built underground hangars is Jiashan Airbase, located in Hualien at Eastern Taiwan coast, to prevent from massive missile strike launched from China. Underground hangars in Jiashan Airbase has deployed F-16 A/B, F-5 E-F squadrons.
Saudi Arabia 
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