SAN FRANCISCO (CBS SF) — Inbound flights to San Francisco International Airport are experiencing an average delay of almost four hours, due in large part to a runway out of service for reconstruction, according to the website FlightAware.

Runway 28L, one of SFO’s four runways, closed Saturday for a scheduled 20-day reconstruction, which is also affecting two other runways off and on as crews try to get the work done.

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The construction started at 12:01 Saturday morning and is expected to wrap up by September 27.

As of Sunday night, a spokesperson with the San Francisco International Airport said 358 flights have been delayed and 137 have been canceled, leaving a lot of frustrated passengers waiting out the delays at the airport.

“For me it’s frustrating because I don’t deal with change very well and it was a last minute change,” said Hortencia Morales from Sacramento. Her flight from Sacramento was canceled and nearly three hours later, she arrived at SFO after catching a ride. She’s not the only one suffering the impact of the delays.

Chris Woolley flew in from Las Vegas, where the plane sat on the tarmac for an hour. “It was horrible,” Woolley said. “We just sat on the plane for an hour, with very little information.”

The construction is even slowing down traffic outside the airport as 600 trucks go in and out of the entrance on Old Bayshore Highway and Millbrae Avenue daily.

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Chuck Navigante, an SFO duty manager, said the biggest reason by far for the delays and cancellations is the runway work.

“It’s pretty much going to remain this was for the duration of the runway work,” he said.

The delays are impacting international travelers the most–once they miss their connection, they often have to make overnight accommodations until the next batch of flights head out in the morning.

The airlines have cut the number of flights at SFO by about 14% during the construction project.

Airport officials ask that anyone planning to fly out of SFO in the next 19 days, or meet an arriving flight, to check with the specific airline on the status of any given flight before making plans. Officials also suggested travelers book early morning flights that depart before 9 a.m. during the runway shutdown.

The worst travel days are expected to fall between Wednesday and Friday, officials said.

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