I'm not sure "knock" is the right word.

CityJet was set up by Pat Byrne initially to serve the DUB-LCY market for which he believed there would be demand but which most people told him would never work. The route started in 1994, under the Virgin brand for the first year or so, and the airline has always served the route since, though others (including Aer Lingus, who, according to Byrne himself in the book he wrote about the whole CityJet saga, only took on the route in a mean-spirited attempt to drive them out of business) have come and gone on that route through the years.