Why does the Catholic Church have a vested interest in chaplaincy at airports? Simply put, providing pastoral care for people on the move is a special concern for the Catholic Church. It is summarised in the two greatest commandments, that being "love of God" and "love of neighbour".
More than that, Airport Ministry is a mission of proclaiming the Good News, a work of evangelisation that takes place in airports around the world.
Since 1970, the Toronto Airport Catholic Chaplaincy has been a ministry of the Archdiocese of Toronto, in conjunction with the Pontifical Council for Pastoral Care of Migrants and Itinerant People.
http://saltandlighttv.org/catholicfocus/flying-with-faith.php