Knock in Ireland
has an international airport, the fourth largest in Eire. It's there to handle the half-million or so Catholic pilgrims who visit the nearby shrine every year. Religion is big business in the travel industry.
Oh, and Lourdes? From the Wiki article on the airport at Knock:
"On 1 June 2003, hundreds of people gathered to view an Air Atlanta Icelandic Boeing 747 land with 500 returning pilgrims from Lourdes."