Australian airline Qantas, which is backed by the country’s government, has delayed flights over the Southern Indian Ocean because of last-minute changes to planned activity from the private aerospace company helmed by Elon Musk. These delays are up to six hours.

“Over the past few weeks we’ve had to delay several flights between Johannesburg and Sydney due to advice received from the US Government regarding the re-entry of SpaceX rockets over an extensive area of the Southern Indian Ocean,” Ben Holland, the head of Qantas’ operations center, told Fortune in a statement.

South African Airways is also experiencing delays because of SpaceX flights, the Guardian reported. The airline and SpaceX did not respond to Fortune’s requests for comment.

SpaceX could launch Starship rockets up to 400 times in the next four years, SpaceX President Gwynne Shotwell told investors in November, fueling a billionaire space race and bolstering Musk’s mission to return astronauts to the moon and eventually colonize Mars. On Wednesday, a SpaceX Falcon 9 lifted off from NASA’s Kennedy Space Center in Florida with two moon landers in tow. NASA agreed to pay SpaceX $3 billion for its Starship rockets.

SpaceX disruptions have been an expensive and time-stealing headache for commercial airlines for years. In 2018, a SpaceX Falcon Heavy launch in Florida forced 1,000 miles of airspace to close for three hours. It caused 563 flight delays totalling 4,645 minutes (about 77 hours) and required planes to fly an additional 34,000 miles to circumvent the closure, according to a 2019 Congressional report. The EmbryRiddle Aeronautical University found that a single spaceship launch could cost commercial airlines up to $300,000 in extra fuel as planes navigate diversions.

What caused the Qantas delays?

Qantas’ recent delays are a result of the unpredictability of when exactly rocket components will return back to earth and cause airspace disruptions. The rockets assisting in the launch of ships like Space X’s Falcon 9 are disposable and fall back into the Earth’s atmosphere, splashing into the ocean.

But if airlines don’t know exactly when and where these pieces of debris re-enter Earth, they can’t effectively plan flight paths needed to divert perimeters where debris is predicted to land. This can cause last-minute delays.

“While we try to make any changes to our schedule in advance, the timing of recent launches have moved around at late notice which has meant we’ve had to delay some flights just prior to departure,” Holland said. “Our teams notify customers of changes to their flight as soon as we know it will be impacted.”

Holland said the airline is in contact with SpaceX to generate solutions to minimize commercial flight delays.

A challenge for the FAA

The disruptions rocket launches can cause commercial flights puts the Federal Aviation Administration in a challenging position. SpaceX has lambasted the regulatory body for its slow approval of vehicle testing and launching with SpaceX president Shotwell saying in November, “All we ask is regulate industries. Make them safe, make them right, make them fair. But we’ve got to go faster. Much faster.”

The FAA approved a record 148 licensed commercial space operations in 2024, 30% increase from the year before.

The regulatory body also oversees traffic control centers and can stop a flight from flying within a certain radius of where debris is expected to land. The FAA introduced the Space Data Integrator in 2021, which can more directly share data about when and where rockets launch and re-enter Earth. The more precise data allows the FAA to accurately reduce the amount of time needed to close airspace perimeters.

“The end goal is to ensure we can optimize the safety, efficiency, and integration of space operations using our advanced automation tools and procedural improvements,” the FAA said of the project.