Spotters at Kona International Airport (KOA) in July 2024 witnessed an unusual sight when a Boeing 777-9 visited the airport. Officially, the plane visited for testing, as it remains in active development. Beyond just being an in-development aircraft, the Boeing 777-9 is also the biggest aircraft currently on sale, and could be considered as the largest Boeing ever built (being lighter with a smaller fuselage than the 747-8, but having a larger wing with a longer fuselage). It’s the biggest plane to visit the Hawaiian Islands in recent history, which begs the question, why Kona?

KOA is not a large airport. As the primary airfield serving Hawaii’s Big Island (with the other being Hilo International Airport (ITO)), it receives a decent amount of passengers and is ranked third in the archipelago, behind Honolulu and Kahului, but it only receives passenger flights from North America. The largest passenger aircraft to regularly serve Kona today is United Airlines’ Boeing 787-10, operating seasonally from Chicago O’Hare International Airport (ORD), and this is also Kona’s easternmost nonstop destination.

The Boeing 777-9 Visiting Kona

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The Boeing 777-9 is a member of the Boeing 777X family. The 777X is the third-generation of the Boeing 777, featuring a stretch of the 777’s metal fuselage, along with a new carbon-composite wing, an improved cabin, an updated cockpit, and new General Electric GE9X engines. The 777-9 is the first variant of the 777X family, intended to succeed the 777-300ER, and it is also the largest variant of the 777X family. The 777-8F will come second, succeeding the 777F, while development of the 777-8 (succeeding the 777-200LR) is on hold.

KOA has an 11,000 feet (3,353 meters) runway, which is more than enough for the 777-9, but facilities in Kona are minimal otherwise. The main passenger facilities consist of sets of open-air tropical-style structures divided into two terminals, along with a general aviation ramp that accommodates commuter flights. In other words, it’s hardly the type of airport that the 777-9 will visit once it enters commercial service, as these planes will instead frequent airports like John F. Kennedy International Airport (JFK) in New York, London Heathrow Airport (LHR), Dubai International Airport (DXB), and Singapore Changi Airport (SIN).

Boeing flew the 777-9 to KOA for development testing. The 777-9 has, in fact, visited the airport numerous times during flight testing, and the 777X’s thrust link issue that grounded the test fleet for months in 2024 was discovered after a flight from Kona. Ever since testing resumed in January 2025, the 777-9 has continued to visit Kona, in addition to visiting other unexpected airports such as Curaçao International Airport (CUR) in the Caribbean.

Choosing Kona For Testing

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Most recently, Boeing has been performing engine oil cooling and nacelle cooling tests for the 777-9 at KOA. The aircraft continues to visit the airfield even in 2026, and in addition to the tests that are performed on the ground, Boeing performs certification flights to and from the airport with FAA staff onboard. It’s one of the airports that the 777-9 visits most often, and while it’s not publicly disclosed why Boeing chose Kona, it’s likely due to a combination of its location and traffic volume.

Kona International Airport is less busy than Kahului or Honolulu, but its runway is still long-enough to easily accommodate the 777-9. Lihue and Hilo both have shorter runways than Kona, and even Kahului’s runway is significantly shorter than that of Kona’s. Hawaii has a relatively hot and humid climate, which makes it ideal to perform oil and nacelle cooling tests, and the conditions also allow Boeing to monitor wear and tear on the test aircraft.

Hawaii is located several hours from the mainland United States, and lying between the two is just the Pacific Ocean. As such, flying the 777-9 from Everett to Kona allows Boeing and the FAA to monitor the aircraft’s performance on longer routes over the ocean, but the flight is also not a long-haul route. This decreases risk since the plane is still in testing. Boeing has also flown the 787 to Kona when that aircraft was in testing, and even tested the original Boeing 777 in Kona in the 1990s.

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Other Airports Being Visited By The Boeing 777-9

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As the location of the final assembly line for the 777, Paine Field is the origin of many Boeing 777-9 test flights, and the plane also performs a significant amount of testing at Boeing Field. The 777-9 test fleet has visited multiple nearby airports in the Pacific Northwest, such as Moses Field and Spokane. These flights are all quite short, primarily measuring aircraft performance and occasionally performing maneuvers such as touch-and-goes.

The 777-9 occasionally visits CUR, largely for the same reason that it visits Kona. Curacao’s hot and humid climate allows Boeing to measure how the aircraft’s components and systems are affected by such conditions. In addition, you’ll often find the 777-9 visiting airports in the United States, like Victorville, Edwards Air Force Base, or Pinal Air Park. In some cases, the planes are visiting for flight testing, and in other cases, Boeing performs ground or takeoff tests.

The common denominator is that Boeing is selecting smaller airports with low flight traffic volumes. This ensures both that testing isn’t disrupted by regularly scheduled commercial service and that the tests aren’t disrupting regular flight traffic either. An airport such as Kona or Curacao may receive regular passenger flights, limiting Boeing to performing tests on the ramp, but airfields like Victorville may receive little to no commercial flights, allowing Boeing to perform more extreme testing, such as VMU tests.

The Certification Of The Boeing 777X

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The development process for the Boeing 777-9 is one of the longest in modern history. Boeing launched the 777X program in 2013 and initially planned for the aircraft to enter commercial service in 2020. The 777-9 has now been in development for 13 years, and its entry-into-service has most recently been pushed back to 2027, a delay of seven years. When the first 777-9 was completed in 2019, it was anticipated that certification could be achieved just one year later, but the delays keep on mounting.

After the fatal crashes of two 737 MAX 8 aircraft in 2018 and 2019, the FAA came under heavy scrutiny for essentially permitting Boeing to self-certify aspects of the aircraft’s design. With the 777-9, the FAA has thoroughly overhauled its certification standards to be more comprehensive. The downside is that the standards are sometimes subject to interpretation by individuals, and these standards are changing. In other words, the FAA is unsure of what it wants from Boeing, leading to a significant slowdown in the certification process.

The 777X is now in Phase Three of the Type Inspection Authorization process. Although there are five phases, the phases are broken down into numerous stages, and there are nine in total. Phase Three is the longest and most rigorous of the five, with Phases Four and Five being significantly shorter than prior phases. In addition, once the nine stages of certification are complete, Boeing will then need to gain ETOPS certification for the 777X. Although Boeing has yet to announce any further delays, there is potential for the 777X’s certification to be pushed back even more.

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Boeing’s Other Aircraft Projects

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Boeing is prioritizing the 777-9 as this is the 777X variant with the most amount of orders. The 777-8F is the cargo version of the 777X, and this aircraft is currently expected to enter service in 2028. The 777-8 is the passenger variant of the 777-8F, but development of the aircraft has been paused to focus on the 777-9 and 777-8F, as the 777-8 has received very few orders. It remains to be seen if the 777-8 will ever be developed, although it should have extremely high commonality with the 777-8F.

Currently, Boeing is only delivering two variants of the Boeing 737 MAX (737 MAX 8 and 737 MAX 9) as the 737 MAX 10 and 737 MAX 7 are also in development hell, like the 777X. The 737 MAX 7 has received only a few hundred orders, mainly from Southwest Airlines, but the 737 MAX 10 is now the second-best-selling variant of the 737 MAX family. behind only the 737 MAX 8. The 737 MAX 10 is plenty capable in its own right and will have incredible operating economics, making it extremely appealing to airlines.

Boeing is experiencing the same prolonged certification challenges with the 737 MAX 10 as with the 777X. Boeing is aiming to certify the 737 MAX 10 in late 2026 and is aiming to deliver the first production 737 MAX 10 to launch operator WestJet in 2027. Of course, it remains to be seen if this timeline holds, which itself has slid back by several years from its original target of 2020.