CHICAGO — Former Air Canada CEO Robert Milton will be named non-executive chairman of United Continental Holdings at the company’s annual meeting in June.

Milton headed up Air Canada’s parent company ACE Aviation Holdings Inc. from 2004 to 2012.

Disgruntled United Continental Holdings investors had accused the company’s board of lacking airline expertise. Over the past several years the company’s stock returns and performance have fallen behind those of its competitors. CEO Oscar Munoz said United looks “forward to working constructively together as we build upon United’s increasing positive momentum.”