Former Abta chairman McEwan is joining Latin Routes, a specialist operator to South America.
He becomes chairman of the business, formed in 2012 by Jessica Bain and Martin Johnson, on July 1.
The operator specialises in Argentina, Peru, Brazil, Chile and Antarctica by selling direct and through the trade.
McEwan said: “This is a young company, led by a great team in Jessica Bain and Martin Johnson who offer customers a fantastic and personalised experience.
“The company has great potential and I want to use my experience and industry contacts to help them grow.”
Bain and Johnson, directors of Latin Routes, said: “We are delighted to have John join our board with his expertise and experience in the industry.
“We are looking forward to growing Latin Routes together and are excited to learn from someone so well respected and successful.”
Besides becoming the first chairman of Abta, McEwan was chief executive of Advantage Travel Centres as well as holding senior roles at Thomas Cook and Tui.
He is non-executive chairman at Holidaysplease.com and EFR Travel Group, is a non executive director of Ski Solutions and is also vice chairman of People 1st. McEwan is also chairman of the advisory board of Pebble Travel Investors.