SAN FRANCISCO (KGO) -- Construction on San Francisco International Airport's busiest runway has been going on for three days, and the impact isn't getting any better.
Hundreds of flights have been delayed or canceled since the maintenance project began Saturday.
Some airlines have rerouted their flights through other local airports to the surprise of some passengers.
RELATED: SFO flight delays, cancellations increase on 2nd day of runway construction
"We had Jet Blue and it said last night that we were supposed to board at 4 pm, and then this morning it said we were supposed to leave at 2:30 in the morning," Analesia Hudgins, who was flying with her Uncle Kevin from SFO to Orange County, said. "Then we went to Jet Blue's front desk and they said there's no Jet Blue flights leaving anymore out of here and we have to go to Oakland now."
At Oakland International Airport, an Alaska Airlines employee said at least eight flights had been rerouted from SFO to Oakland. A spokesperson for San Jose International Airport said every day at least six Alaska Flights have also rerouted through their airport.
At SFO, ABC7 News found travelers sleeping in terminals and almost too many cancellations to count on the big board inside SFO Monday morning. The airport was off to a rough start on day 3 of its 20-day runway closure.
By 5 pm Monday night, nearly 300 flights had been delayed and 124 flights cancelled, according to SFO.
Brenda Wong is traveling from Hong Kong and trying to get home to Oregon. United Airlines contacted her early, offering an opportunity to rebook.
"They said I could change it for free, but it's not possible because it's an international trip for me," Wong said. "So, I just took the chance and obviously I lost. That's why I am here for a long time, because they cancelled two flights consecutively."
Wong was supposed to leave around 8am, then 11 a.m., now she's hoping the 4 pm flight works out.
Elaine Ratner was prepared for the runway construction. Her flight to Philadelphia was pushed back two hours.
"Yes, I was told ahead of time," Ratner said. "But, I rather sit at the airport than leave at 9 o'clock tonight."
"Although the project is focused on runway 28L, the work is actually happening where that runway intersects with two other runways," Doug Yakel, SFO's spokesman said. "One left and one right."
When you've got two of your four runways closed, the impact is bound to be significant. The affected flights have primarily been the short haul trips up and down the west coast.
"That's really where the greatest frequency of flights in and out of SFO are occurring," Yakel said.
"I woke up this morning hecka early," Hazel Molano, an Antioch resident, said. "Took BART to get here."
Molano's flight to Phoenix was also delayed about two hours. However, the wait isn't all bad. She had extra time to spend with her father at the airport.
Airport officials recommend travelers reach out their airlines to explore rebooking or rerouting opportunities.
SFO now rerouting flights through Oakland, San Jose airports due to runway closure