Thousands of flights across the East Coast were delayed on Sunday as thunderstorms and a computer systems failure kept planes grounded. The disruption hearkened back to last summer’s flight chaos, where U.S. airlines canceled or delayed thousands of flights.
Now, a new headache for airlines will trigger this coming Saturday, right in the middle of the July Fourth holiday weekend.
Starting July 1, U.S. planes that have not been retrofitted to withstand interference from new 5G wireless signals may not be allowed to land in some low-visibility conditions, warned U.S. Secretary of Transportation Pete Buttigieg in a letter on Friday to Airlines for America, an association representing U.S. airlines.
Most U.S. planes have been upgraded to meet the new standards—but not all.
“There’s a real risk of delays or cancellations,” said Buttigieg in a Friday interview with the Wall Street Journal. It’s “one of the biggest—probably the biggest—foreseeable problem affecting performance this summer,” he said.
The Saturday deadline is the culmination of a long argument among airlines, wireless companies, and the U.S. government.
Airlines were worried that an expanded 5G network from companies like Verizon and AT&T would interfere with equipment on older airplanes, particularly radio altimeters, which measure how high a plane is above the ground. The Federal Aviation Administration warned that airlines might be forced to cancel flights if plans to expand 5G went ahead.
Wireless companies agreed in early 2022 to delay the expansion of 5G near major U.S. airports until July of this year, defusing the crisis and giving airlines time to upgrade their fleets.
Airlines have made progress since then: Over 80% of domestic planes can now fly free from interference, Buttigieg told the Wall Street Journal.
American Airlines, Southwest Airlines, and Frontier Airlines have completed their retrofits, while United Airlines will meet the July 1 deadline for its “mainline” planes, according to the Associated Press. JetBlue expects its planes to be ready by October, and forecasts “limited impact” on its Boston flights until then.
Delta Airlines is an outlier, as the airline admits that 190 of its planes, or 20% of its fleet, won’t be ready by July 1, according to the Wall Street Journal. The carrier blames supply-chain issues for the delay.
“Global supply chains continue to lag behind current demand. Carriers have repeatedly communicated this reality to the government,” Airlines for America, the association of U.S. carriers, said in a statement provided to the Wall Street Journaland other outlets. Airlines for America did not immediately respond to Fortune’s request for comment.
International carriers are behind their U.S. peers, with only 65% of international planes having undergone the necessary retrofits, estimated Buttigieg in his Wall Street Journalinterview.
A 2023 flightmare?
Last year was brutal on airlines. Carriers tried to tap into a huge boom in “revenge travel” spending, yet were overwhelmed owing to limited staff and planes. Bad weather and outdated computer systems also contributed to flight delays and cancellations.
In the days ahead of last year’s Independence Day weekend, a third of flights arrived late, and airlines canceled 2,500 flights.
The Biden administration is now paying attention to flight schedules, and proposed new rules earlier this year to require airlines to compensate passengers for additional costs, like accommodation or transportation, incurred as the result of a flight delay.
Almost 51 million people are forecast to travel for this year’s July Fourth weekend, predicts the American Automobile Association. Around 4 million of those are expected to travel by plane, a 6.6% increase over 2019.