1. Cover stories and hidden agendas: early American space and national security policy;Day,2000
2. Space tourism, private spaceflight and the law: Key aspects;von der Dunk;Space Pol.,2011
3. However, many of privately invested startups later collaborates with or receive funding from the government so fully private space companies are not many.
4. See ICAO, Space Transportation. https://www4.icao.int/space, (accessed on 6 July 2018); “Democratization of Space” is also a similar concept that, increasing number of small-to-medium sized companies as well as entrepreneurs are involved in space activities. See W. Welser IV, The Democratization of Space, The RAND Blog. https://www.rand.org/blog/2016/03/the-democratization-of-space.html, 28 March 2016 (accessed on 6 July 2018); These commercial space companies, whether by supporting government space programs or selling goods and services to other companies or private individuals, are driving innovations to expand now estimated USD350 billion a year space market to one trillion by 2040s. See J. Foust, A trillion-dollar space industry will require new markets, SpaceNews. http://spacenews.com/a-trillion-dollar-space-industry-will-require-new-markets/, 5 July 2018 (accessed on 6 July 2018).
5. Air Laws refer to, Convention on International Civil Aviation, signed at Chicago, on December 7, 1944 ("Chicago Convention") ICAO Doc.7300/8