William Matthew Walsh (born 25 October 1961) is an Irish airline executive who is currently the Director General of the International Air Transport Association.

[2] He acquired a Master's degree in management and business administration from Trinity College, Dublin during his pilot years, while advancing to become a Boeing 737 captain.

[2][3] In October 2001, Walsh was elevated from COO to CEO of Aer Lingus, succeeding Michael Foley, who had resigned following a harassment complaint.

[citation needed] The management team suggested to the principal shareholder, the Irish Government, a float of Aer Lingus on the stock market.

Stock floats are often rewarding to top management and this was opposed by the unions who feared a privatised Aer Lingus would impose even tougher working conditions.

He described the closure of European airspace in April 2010 over worries about the ash plume from an erupting Icelandic volcano as a "gross over-reaction to a very minor risk".

[12] Walsh oversaw the merger of British Airways and Iberia forming a new holding company International Airlines Group (IAG) in January 2011.