The Globe and Mail reports in its Wednesday edition that Canada's biggest pension funds have pushed back hard against calls to invest more in the domestic economy. The Globe's Konrad Yakabuski writes that there is at least one sector in which they would be thrilled to stash more of future pensioners' cash without arm-twisting -- the country's capital-starved airports. Most of the Maple 8, as Canada's eight largest pension funds are collectively known, have been investing in foreign airports for years, capitalizing on a global boom in air travel. Despite the huge carbon footprint of big jets, more people than ever are flying, but the airports cannot sell stock to raise capital. That has left them too dependent on debt financing and dreaded "airport improvement fees" to fund infrastructure upgrades and much-needed digital investments to improve service. That could soon change. In last month's federal budget, Finance Minister Chrystia Freeland singled out airports as a possible candidate for pension-fund investment that a new working group led by former Bank of Canada governor Stephen Poloz has been mandated to explore. Just how far Ottawa is prepared to go to open up airports to outside investors remains to be seen.