Airlines are not able to conduct their business in the same way as other global transnational industries. They are inhibited by the foreign ownership restrictions in Air Services Agreements and national laws. This paper reviews the background of nationality clauses and the current regulations in the EU, US and Asia-Pacific. It analyses the pros and cons of ownership rules, the benefits and risks of foreign investment, and the motives for foreign investment in the EU and Asia-Pacific. It also assesses the prospects for change in ownership rules under multilateral and plurilateral proposals.