American Airlines has a huge transatlantic footprint, linking various US hubs with destinations all over Europe. On some routes, the Fort Worth-based oneworld founding member competes with its US ‘big three’ legacy rivals (SkyTeam’s Delta Air Lines and Star Alliance’s United Airlines) and European heavyweights, while, elsewhere, it has more of a monopoly. Regardless, it always wants every seat filled.

According to historical load factor data made available by Cirium, an aviation analytics company, American Airlines averaged an occupancy rate of 85.01% across its transatlantic flights in the 12 months to June of 2026. However, 11 of these routes fell some way short of this mean figure, clocking in at below the 80% mark. Let’s take a closer look at where they are, and how they compare to the top routes.

The Four Emptiest Routes All Serve The UK

Credit: Abdul N Quraishi – Abs | Shutterstock

Straight off the bat, an interesting thing to note about American Airlines’ emptiest routes is that the top (or should that be bottom?) four all serve airports in the United Kingdom. These are detailed in the interactive map embedded below. The worst performer in 2025/26 was Raleigh-Durham International Airport (RDU) in the US state of North Carolina to London Heathrow (LHR), with a figure of 73.3%.

Two of the other three emptiest routes also served London Heathrow, with American Airlines’ flights from John F Kennedy International Airport (JFK) in New York City averaging 75.98%, compared to 76.29% from Boston Logan International Airport (BOS). Elsewhere, JFK to Edinburgh was the second emptiest overall, at 74.78%. Brian Znotins, AA’s SVP of Network and Schedule Planning, said of this route that:

“With the game-changing Airbus A321XLR now in our fleet, we could not be more excited to connect the Big Apple with Auld Reekie. This is the right aircraft to open this route.”

Seven More Corridors Dip Below The 80% Mark

Credit: Great Circle Map

Moving further down the list, and away from the United Kingdom, the top five is rounded out by the corridor from Charlotte Douglas International Airport (CLT) in North Carolina to Munich Airport (MUC) in the state of Bavaria in the southeast of Germany. These flights were 77.13% full on average in 2025/26, compared to 77.57% for the much longer route from Los Angeles (LAX) to London Heathrow.

Returning to the East Coast of the United States of America, the seventh-emptiest of American Airlines’ many routes across the North Atlantic Ocean links Philadelphia International Airport (PHL) in Pennsylvania with Zurich Airport (ZRH) in Switzerland. This corridor had a mean load factor of 78.46%, compared to 78.73% for eighth-placed Charlotte Douglas International Airport to Frankfurt, Germany (FRA).

Returning to Philadelphia, flights from here to Schiphol Airport (AMS) in the Dutch capital city of Amsterdam were 79.38% full in 2025/26, with Dallas/Fort Worth International Airport (DFW) to Zurich’s figure of 79.82% seeing this route round out the top ten. Las Vegas (LAS) to London Heathrow was the last sub-80 route (79.96%), although only a handful of short-term flights operated in conjunction with CES 2026.

What About The Best Performers?

Credit: Great Circle Map

At the other end of the load factor spectrum, four different transatlantic American Airlines routes exceeded the 92% mark in the 12 months to June of 2026, comfortably beating the aforementioned overall mean figure of 85.01%. The best overall performer was Chicago O’Hare International Airport (ORD) in Illinois to Athens International Airport (ATH) in Greece, which managed a strong mean of 93.62%.

Elsewhere, the second and third-busiest American Airlines routes to Europe in 2025/26 both originated at Dallas/Fort Worth International Airport in the US state of Texas. Their destinations were Madrid Barajas Airport (MAD) in Spain and Rome Fiumicino Airport (FCO) in Italy, with respective load factors of 92.31% and 92.29%. Rounding out the top four, AA’s Miami (MIA) to Madrid flights were 92.06% full.