Pablo Mendes de Leon studied at the University of Utrecht in the Netherlands from 1974 to 1979. He continued his studies at the University of Paris 2, and during this period he also followed a training programme at the Organisation of Economic Co-operation and Development (OECD) in Paris. Subsequently, he worked for the EC Delegation at the United Nations in New York. In 1981, he started his professional career at the law firm Barents and Krans in The Hague, where he practised European Community Law, company law and bankruptcy law.

In 1985, Mendes de Leon joined Leiden University, where he obtained his doctoral (PhD) degree (with honours) in 1992 on a thesis entitled "Cabotage in International Air Transport Regulation". In addition to his teaching position, he acted as Director of the International Institute of Air and Space Law. In this capacity, he organised a number of international conferences on topical developments in international aviation and space law. Besides his academic research as a Meijers Fellow, Mendes de Leon carries out studies for third parties. From 2003 until 2007, he was Director of Air Law Research at the International Institute of Air and Space law. He lectures private international air law and competition law in the Institute's Advanced LL.M. programme. Moreover, he is a regular speaker at conferences on international aviation developments. 

Professor Mendes de Leon maintains memberships in organisations that work to combine air and space law and education including: 

• President, European Air Law Association (see: https://eala.aero) 
• Honorary Judge, District Courts, The Netherlands
• Honorary President, Student Association "Telders" on International Law, Law Faculty, Leiden University
• President European Air Law Association 
• Membre de l’Acadérmie de l’Air et de l’Espace (Toulouse)
• Member Editorial Board, Air and Space Law magazine (Kluwer)
• Fellow, Meijers Institute, Leiden University
• Board Member, KLM-Air France foundation
• Chairman Foundation SAK-I
• Member, Air Transport Commission of the International Chamber of Commerce, Paris
• Board member, Brazilian Institute of Strategic Studies and Policies in Air Transport, Rio de Janeiro; Member, International Faculty, IATA Learning Centre, Geneva 
• Member, Advisory Board, Journal of Air Law and Commerce
• Member Editorial Board, Aviation Maritime Journal (Bologna, Italy) 
• Series Editor, Aviation Law and Policy, Kluwer Law International
• Member, Advisory committee of the Korea Institute of Air & Space Law, Hanul Professional Law Corp; Correspondent, Editorial Board, Netherlands' Association for Public Transport Law
• Member, Advisory Board Asian Institute of Air and Space Law
• Member, Council of the Foundation for Aviation and Sustainable Tourism, Delhi, India
• Member, International Panel of Experts, Gujarat National Law University, Gandhinagar, India
• Member, Supervisory Board, "Aerius", Amsterdam
• Fellow, AirNeth, Amsterdam/The Hague
• Member, Advisory Academic Board, Airneth, Amsterdam
• Main publications Conferences Research NAA EALA 
• Main publications of Professor P.M.J. Mendes Leon

Publications