Passengers aboard an American Airlines flight to Naples, Italy, had to be bused over 140 miles to their destination from Rome because their plane was seemingly too big to land in Naples.

The Boeing 787-9 Dreamliner departed Philadelphia at 7:10 p.m. on Monday, June 2, FlightAware shows. The flight was supposed to land in Naples around 9:10 a.m. the next day, but an American Airlines spokesperson told USA TODAY on June 7 that "operational limitations" led to the diversion and eventual landing at the Leonardo da Vinci International Airport (FCO) in Rome at 9:43 a.m. on June 3.

"Customers traveled from FCO to NAP by bus, and we apologize to them for this disruption to their journey," the American Airlines spokesperson said in a statement.

FCO is about 145 miles away from Naples International Airport by road, meaning it would typically take more than two hours to drive between the airports.

What may have caused the American Airlines flight to divert?

Historical flight data via FlightAware shows American Airlines usually sends a Boeing 787-8 on flights to Naples. It is unclear why the airline sent the larger 787-9, which Simpleflying, an online aviation publication, says fits 290 passengers compared to the 787-8's 242 passenger capacity. Another key difference between the two Dreamliner variants, which have the same wingspan, is that the 787-9 is 20 feet longer, according to Business Insider.

The 787-9 may have been diverted because it has different requirements for rescue-and-firefighting services (RFFS) than the 787-8, documents from Boeing and the International Civil Aviation Organization show. RFFS are needed to ensure aviation safety and minimize risks related to aircraft fires and incidents, according to the Federal Aviation Administration (FAA).

While the 787-8 is small enough to land at an airport with Category 8 RFFS requirements, the 787-9 needs a Category 9 RFFS airport, the Boeing document shows.

Data reviewed by Business Insider from AviationWeek's Acukwik says the Naples Airport meets Category 8 RFF, meaning a 787-9 would be too big to land there.

Jonathan Limehouse covers breaking and trending news for USA TODAY. Reach him at JLimehouse@gannett.com.

This article originally appeared on USA TODAY: American Airlines passengers bused over 140 miles in Italy after diverted flight

Reporting by Jonathan Limehouse, USA TODAY / USA TODAY

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