The busiest international flight route in every region of the globe, according to flight data

- Seats sold: 3,878,590
- Rank among all 2023 international flights: #8
- 2022 rank: #4
- Change from 2022 to 2023: +24%

Both major cities in their respective regions, it comes as no surprise that flights between these two maritime cities are so popular. Traveling from one to the other has even been coined making a "transatlantic crossing."

JFK to LHR is not only a popular route for leisure tourism but also an important route for travelers making connections to continue to other parts of the world. On top of that, business travelers frequently fly between JFK and London Heathrow to conduct business in these major cities.

There are about 20 flights per day on multiple airlines from New York's JFK Airport to London's Heathrow Airport. While other top 10 international routes have yet to recover their pre-pandemic capacity, this JFK to LHR route is already there, offering more seats than it did before COVID-19.

- Seats sold: 4,891,952
- Rank among all 2023 international flights: #1
- 2022 rank: #3
- Change from 2022 to 2023: +50%

Once a British colony along with Malaysia, Singapore was originally part of the Federation of Malaysia when it was formed in 1963. Singapore eventually left to become an independent state two years later, but historical and economic ties continue to this day, which are evident in this flight's popularity.

Southeast Asia's flight from Kuala Lumpur to Singapore may be the shortest flight on this list, but it's also the busiest. This short flight outranks its closest competitor (the flight between Cairo to Jeddah) by almost 100,000 seats in 2023. Flight time between Malaysia's capital and its neighboring island country is about an hour. Travelers can also make the trip by train, bus, or car, but the journey takes a little longer; between four and seven hours.

Singapore's airport has established itself as a key international hub. Seven of the top 10 busiest international routes in Southeast Asia start or end in Singapore.

- Seats sold: 2,436,988
- Rank among all 2023 international flights: Not in top 10
- 2022 rank: data not available
- Change from 2022 to 2023: data not available

Although this is technically a route between two U.S. cities since Puerto Rico is a U.S. territory, Puerto Rico is also considered a Latin American destination due to its colonization by Spain. Florida, too, was once a Spanish colony, and today, the state is home to the largest Puerto Rican population in the country.

Puerto Rican migration to Florida began in the late 19th century when most Puerto Ricans settled around the Tampa Bay area. Since the 1980s, however, the community has moved to Orlando and the surrounding communities in Orange County. The Orlando to San Juan route has 129 weekly flights from four airlines: Southwest, Jet Blue, Frontier, and Spirit Airlines.

- Seats sold: 4,795,712
- Rank among all 2023 international flights: #2
- 2022 rank: #1
- Change from 2022 to 2023: +38%

The flight route between Cairo, Egypt to Jeddah, Saudi Arabia was the second busiest route in the world for 2023. It was the busiest route of 2022 but was overtaken slightly by last year's tremendous 50% airline capacity growth of the KUL-SIN route.

Flights to Saudi Arabia have been prominent for decades for the world's nearly two billion Muslims, who are instructed to make a pilgrimage to Mecca in Saudi Arabia at least once in their life. In Egypt, almost 95% of the population is Muslim. Beyond religion, the two Middle East regions also share political and economic ties with 3 million Egyptians working in Saudi Arabia in 2020.

In addition, since 2019, Saudi Arabia has also begun marketing itself as a destination for leisure tourism, identifying seven destinations (including Jeddah) as key areas of focus. Jeddah is also one of the country's main city destinations for business travelers.

Story editing by Carren Jao. Copy editing by Robert Wickwire.