These 10 global flight routes are where airlines made the most money in 2018 and 2019

With four daily flights between the two Asia-Pacific economic hubs, Singapore Airlines earned $549,711,946 in revenue. Despite competing with the likes of Qantas and British Airways, as well as low-cost subsidiary Scoot, Singapore Airlines dominated the route with two of its four departures being operated by the Airbus A380 and the other by Boeing 777 aircraft.

The 12-month period saw 26,402 scheduled flight hours bringing in $20,821 per hour. Singapore's Airbus A380s are also known for their extravagant first-class cabins featuring spacious, fully-enclosed suites complete with proper beds, full-screen televisions, and a vanity counter.

Cathay Pacific Airways' route between Hong Kong and London earned the airline $604,595,063 in revenue during the time period for a total of 43,538 scheduled flight hours earning $13,887 per hour. The Hong Kong flag carrier currently connects the two cities with double-daily service on its Boeing 777 aircraft.

The carrier competes with British Airways on the route, which offers a once-daily service on its Airbus A380 aircraft.

The top route for Qatar Airways that connects the capital cities of Qatar and the United Kingdom earned it $639,122,609 during the 12-month span. Qatar Airways currently dominates the skies between Doha and London with six daily departures on aircraft including its new Airbus A350-1000 XWB and Airbus A380, competing with a sole British Airways daily flight operated by a Boeing 787 Dreamliner.

The time period saw Qatar Airways scheduling 31,306 hours of flight time for the route with each hour earning the flag carrier $20,415. The airline is known for its award-winning business class product, known as Qsuites, that is offered on some of the aircraft flying the route. Its A380 aircraft on the route also features onboard bars for premium passengers.

The flagship domestic route for American Airlines earned it $661,739,788 during the time period, making it the second most revenue-generating domestic route in the US. The airline had scheduled 50,519 hours of flight time between New York and Los Angeles, with the route earning $13,099 per hour despite competing with Delta Air Lines, JetBlue Airways, and Alaska Airlines at JFK Airport, as well as United Airlines and Alaska Airlines at Newark Airport.

American Airlines recently gave the route a refresh when it decided to switch to the smaller Airbus A321 instead of continuing wide-body service with aircraft such as the Boeing 767-200. Although the A321 would provide fewer seats for the route, American reconfigured the aircraft to include a first and business class cabin to tailor the route to premium flyers.

United Airlines earned the most revenue on a domestic route in the US with its Newark to San Francisco route. The Chicago-based airline with hubs on both ends of the route brought in $689,371,368 through 53,516 scheduled flight hours that earned $12,882 per hour.

United recently consolidated its transcontinental operations at its Newark hub after shuttering its outstation at JFK Airport that primarily served routes to San Francisco and Los Angeles. The airline flies a variety of aircraft between Newark and San Francisco, including the Boeing 757-200, Boeing 777-300ER, and Boeing 787-10 Dreamliner, each offering business class passengers lie-flat seats.

Singapore Airlines' route between Singapore and London earned it another spot on the top ten list, with the carrier earning $735,597,614 on the route during the 12-month span. The Singaporean flag carrier currently operates four daily frequencies on the route with a mix of Airbus A380 and Boeing 777 aircraft, competing against two daily British Airways flights using the same aircraft and a daily Qantas service on the Airbus A380.

The 39,189 hours of flight time were scheduled during the period with each hour earning Singapore Airlines $18,771 thanks, in part, to the premium offerings onboard.

Emirates joined its Middle Eastern colleague in making money off of service to London with its route to the UK capital earning it $796,201,645 during the time period. The airline currently operates the route with six daily flights, all on its Airbus A380 aircraft that are known for their extravagances including an in-flight shower for first-class passengers.

The airline scheduled 31,943 flight hours between the two cities which each hour bringing in $24,926 in revenue. Emirates had two competitors on the route during the time period, Virgin Atlantic and British Airways, with the former eventually leaving the route in March 2019.

The 381-nautical mile route between Australia's two largest economic hubs generates the most revenue for flag carrier Qantas. Despite its short length, the route earned Qantas $861,260,322 during the time period with 36,229 hours of scheduled flight that made $23,773 per hour.

Even with the route's popularity, Qantas primarily flies its Boeing 737 between the two cities, one of the smallest aircraft in its fleet. The service currently operates hourly throughout the day with no shortage of competitors including Virgin Australia, Tigerair, and Jetstar, with the quartet operating roughly the same daily frequencies.

British Airways was the only carrier to operate a route that generated over $1 billion during the time period, making the London-New York sector the most profitable air route in the world. The UK flag carrier has operated the route for decades and remains one of the most iconic and prevalent carriers on it, competing with airlines such as Virgin Atlantic, American Airlines, and Delta Air Lines.

From April 2018-March 2019, the route earned British Airways $1,159,126,794 with 42,680 hours of scheduled flight time. Each hour of scheduled flight time earned the airline $27,159. The route sees two aircraft used by British Airways — the Boeing 747 and Boeing 777 — with the former due to be retired in the upcoming years.

Though the 747 is aging, its value to British Airways is that it allows for a premium-heavy configuration with a 14-seat first-class cabin, 86-seat business class cabin, and 30-seat premium economy cabin, according to SeatGuru. Only one section of the aircraft features standard economy seats.

The city pair in addition to just the JFK-LHR route is so profitable that British Airways operates additional offerings between Heathrow Airport and Newark Airport, Gatwick Airport and JFK Airport, and London City Airport and JFK Airport. The airline even operates a specially configured all-business-class plane between London City Airport and JFK Airport.