Sofia Airport (IATA: SOF, ICAO: LBSF) (Bulgarian: Летище София, "Letishte Sofiya" ) is the main international airport of Bulgaria located 10 km east from the centre of the capital city Sofia.
 In 2015 the airport surpassed 4 million passengers for the first time and handled a total of 4,088,943 passengers, a 7.2% increase compared to 3,815,158 passengers handled in 2014.
 In 2016, the number rose to almost 5 million passengers.
 The airport serves as the home base for BH Air, Bulgaria Air, and Bulgarian Air Charter and as a base for both Ryanair and Wizz Air.
 The Vrazhdebna Air Base of the Bulgarian Air Force is also located at the airport.
Brussels Airport (IATA: BRU, ICAO: EBBR) (also called "Brussel-Nationaal " / "Bruxelles-National " (Brussels-National) or "Zaventem") is an international airport 6.5 NM northeast of Brussels, the capital of Belgium.
 In 2015, more than 23 million passengers arrived or departed at Brussels Airport, making it the 21st busiest airport in Europe.
 It is located partially in Zaventem, partially in the Diegem area of Machelen, and partially in Steenokkerzeel, in the Flemish Region of Belgium.
 It is home to around 260 companies, together directly employing 20,000 people and serves as the home base for Brussels Airlines, TUIfly Belgium and Thomas Cook Airlines Belgium.
Tallinn Airport (Estonian: Tallinna lennujaam , IATA: TLL, ICAO: EETN ) or Lennart Meri Tallinn Airport (Estonian: Lennart Meri Tallinna lennujaam ) is the largest airport in Estonia and serves as a hub for the national airline Nordica, as well as the secondary hub for AirBaltic and LOT Polish Airlines.
 It was also the home base of the now defunct national airline Estonian Air.
 Tallinn Airport is open to both domestic and international flights.
 It is located 2.7 NM southeast of the centre of Tallinn on the eastern shore of Lake Ülemiste.
 It was formerly known as Ülemiste Airport.
Cobalt Air or simply Cobalt, is a Cypriot airline based at Larnaca International Airport in Larnaca, Cyprus.
 The airline operated its first commercial flight on 7 July 2016 from Larnaca to Athens.
 It is the second Cypriot airline (after Tus Airways) to be established since the dissolution of Cyprus Airways in 2015.
 As of June 2017, it is the second largest airline at Larnaca International Airport with 8.2% of weekly capacity after Aegean, and is predicted to become the largest airline by Summer 2018 following expansion and the subsequent reduction by Aegean at Larnaca.
The University of Michigan Detroit Center (UMDC, U-M Detroit Center or Detroit Center) is a community outreach center, meeting/events facility, and academic home base for University of Michigan units, located in the Midtown neighborhood of Detroit.
 The facility serves as a home base to more than 50 university staff and faculty members from the campuses of the University of Michigan and University of Michigan-Dearborn.
 Providing a visible symbol of the nearly 200-year relationship between the City of Detroit and the University of Michigan, the U-M Detroit Center serves as a gateway for University and urban communities to take advantage of each other’s learning, research and cultural activities.
 The mission of the University of Michigan Detroit Center is to mutually enrich University and Detroit communities through service, education, research and the exchange of culture.
Deutsche Lufthansa AG () (] ), commonly known as Lufthansa (sometimes also as "Lufthansa German Airlines"), is the largest German airline and, when combined with its subsidiaries, also the largest airline in Europe, in terms of fleet size, and the second largest airline in terms of passengers carried during 2016.
 The name of the company is derived from "Luft" 'air' and "Hansa", the Hanseatic League.
 Lufthansa is one of the five founding members of Star Alliance, the world's largest airline alliance, formed in 1997.
Brussels Airlines (stylized as brussels airlines) is the flag carrier and largest airline of Belgium, based and headquartered at Brussels Airport.
 It operates to over 90 destinations in Europe, North America, Africa and Asia and also offers additional charter services, maintenance and crew training.
 The airline is a member of the Star Alliance as well as the International Air Transport Association.
 The airline's IATA code "SN" is inherited from its predecessors, Sabena and SN Brussels Airlines.
 Lufthansa purchased 45% of the company in 2009, and on September 29, 2016, Lufthansa announced it would purchase the remainder of Brussels Airlines for €2.6 million euros.
 The transaction was completed in early January 2017.
Brunei International Airport (Malay: "Lapangan Terbang Antarabangsa Brunei"; Jawi: لاڤڠن تربڠ انتارابڠسا بروني ) (IATA: BWN, ICAO: WBSB) is the primary airport in the nation of Brunei.
 It serves as the home base for Royal Brunei Airlines.
 The Royal Brunei Air Force is also based at the Rimba Air Base, which is located within the airport's area.
 The airport serves destinations across Asia and Oceania as well as flights to London Heathrow (via Dubai).
Singapore Changi Airport (IATA: SIN, ICAO: WSSS) , or simply Changi Airport, is the primary civilian airport for Singapore, and one of the largest transportation hubs in Southeast Asia.
 It is currently rated the World's Best Airport by Skytrax, for the fifth consecutive year (Skytrax's World's Best Airport 2013–2017) and is one of the world's busiest airports by international passenger and cargo traffic.
 The airport is located in Changi, at the eastern end of Singapore, approximately 17.2 km northeast from Marina Bay (Singapore's Downtown Core), on a 13 km2 site.
 It is operated by Changi Airport Group and it is the home base of Singapore Airlines, Singapore Airlines Cargo, SilkAir, Scoot, Jetstar Asia Airways and BOC Aviation.
Ottawa/Macdonald–Cartier International Airport or Macdonald–Cartier International Airport ("L'aéroport international Macdonald-Cartier" in French), (IATA: YOW, ICAO: CYOW) in Ottawa, Ontario, Canada is an international airport named after the Canadian statesmen and two of the "founding fathers of Canada", Sir John A. Macdonald and Sir George-Étienne Cartier.
 Located in the south end of the city, 5.5 NM south of downtown Ottawa, it is Canada's sixth-busiest airport and Ontario's second-busiest airport by airline passenger traffic and Canada's seventh-busiest by aircraft movements, with 4,743,091 passengers and 153,347 aircraft movements in 2016.
 The airport is an Air Canada focus city and the home base for First Air.
 The airport is classified as an airport of entry by Nav Canada and is staffed by the Canada Border Services Agency.
 The airport is one of eight Canadian airports that have United States border preclearance facilities.
 The airport used to be a military base known as CFB Ottawa South/CFB Uplands.
 Although it is no longer a Canadian Forces Base it is still home to the Royal Canadian Air Force's 412 Transport Squadron.

Question: The airport that serves as the home base for the largest airline of Belgium is home to approximately how many companies?
Answer: 260