from Mumbai, Delhi, and Chennai and continued onward to Toronto, New York, and Newark after a near-simultaneous stopover in Brussels and vice versa. An international scissor hub could be used for third and fourth freedom flights or it could be used for fifth freedom flights, for which a precursor is a bilateral treaty between two country pairs. WestJet uses St. John's as a scissor hub during its summer schedule for flights inbound from Ottawa, Toronto, and Orlando and outbound to Dublin and London–Gatwick. At Los Angeles International Airport, Qantas passengers from Melbourne, Brisbane or Sydney may transfer onto a flight to New York–JFK and vice versa. Focus city In the airline industry, a focus city is a destination from which an airline operates limited point-to-point routes. Ergo, a focus city primarily caters to the local market rather than to connecting passengers. Although the term focus city is used to mainly refer to an airport from which an airline operates limited point-to-point routes, its usage has loosely expanded to refer to a small-scale hub as well. For example, JetBlue's New York–JFK focus city runs like a hub, although it is still deemed by JetBlue as a focus city. Fortress hub A fortress hub exists when an airline controls a significant majority of the market at one of its hubs. Competition is particularly difficult at fortress hubs. Examples include Delta Air Lines at Atlanta, Detroit, Minneapolis/St. Paul and Salt Lake City, American Airlines at Charlotte, Dallas/Fort Worth, Miami, and Philadelphia, and United Airlines at Denver, Houston–Intercontinental, Newark and Washington-Dulles. Flag carriers have historically enjoyed similar dominance at the main international airport of their countries and some still do. Examples include Aeromexico in Mexico City, Air Canada in Toronto–Pearson, Air France in Paris–Charles de Gaulle, British Airways in London–Heathrow, Cathay Pacific in Hong Kong, Copa Airlines in Panama City, Emirates in Dubai, Ethiopian Airlines in Addis Ababa, Finnair in Helsinki, Iberia in Madrid, Korean Air at Seoul–Incheon, KLM in Amsterdam, Lufthansa in Frankfurt, Qantas in Sydney, Qatar Airways in Doha, Singapore Airlines in Singapore, South African Airways in Johannesburg, Swiss International Air Lines in Zurich, and Turkish Airlines in Istanbul. Primary and secondary hubs A primary hub is the main hub for an airline. However, as an airline expands operations at its primary hub to the point that it experiences capacity limitations, it may elect to open secondary hubs. Examples of such hubs