Passengers should gear up for flight delays and cancellations this summer as airlines scramble to upgrade their systems to combat 5G interference, Pete Buttigieg says

• Pete Buttigieg warned of "a real risk of delays or cancellations" as a 5G deadline approaches, per the WSJ.
• Telecom companies plan to boost their 5G power levels on July 1, which could interfere with key plane equipment.

This summer could see more travel disruption as a deadline relating to 5G interference threatens to lead to flight cancellations, Transportation Secretary Pete Buttigieg has warned, per The Wall Street Journal.

"There's a real risk of delays or cancellations," Buttigieg said, per The Journal. "This represents one of the biggest—probably the biggest—foreseeable problem affecting performance this summer."

Airlines have until July 1 to update equipment because that's when US telecom companies plan to boost their 5G services to higher levels.

Specifically, there's concern that 5G signals could affect some aircraft's radar altimeters — sensors which measures how high an aircraft is above the ground. The sensors are essential for flying in low-visibility conditions.

Therefore any planes which haven't yet been fitted with the updated equipment won't be cleared to land in weather which produces low visibility, from July 1.

Last month, the Biden administration said it wouldn't extend the deadline despite airlines' concerns and the International Air Transport Association warning that not all aircraft would be updated in time, Reuters reported.

The updated equipment is being installed at the expense of airlines, and estimates say it will cost more than $638 million in total, IATA said in its annual review.

Buttigieg said that around 20% of domestic planes and 35% of international ones which fly to the US aren't yet fitted with the updated equipment, per the Journal.

For Delta Air Lines, supply-chain issues mean about 190 of its 900 airplanes won't have the correct altimeters by July 1, including all of its Airbus A220 planes.

"Many Delta teams have been working to insulate any additional delays from our customers and people through strategic aircraft routing," a Delta spokesperson said. "While we expect minimal operational impact, we continue to work with our supplier to see that every Delta aircraft is equipped with updated radio altimeters."

And a JetBlue spokesperson told the WSJ it expects its 17 A220 jets won't be upgraded until October.

JetBlue did not immediately respond to Insider's request for comment, sent outside US working hours.