The airport started its delay program at 8 a.m. because of the poor air quality and low visibility.
"We couldn't see the ground when we were landing because of the smoke," said Amy Cullen, who had just arrived from Los Angeles.
RELATED: Wet Wednesday could mean tougher Thanksgiving travel
Airport officials were not expecting delays to be as widespread as the past 10 days.
They say the air quality improved making it much better than yesterday when close to 300 flights were delayed according to FlightAware. Tuesday morning's delays were mostly impacting short haul flights up and down the west coast.
RELATED: Check current Bay Area air quality levels
This comes during the holiday travel season. About 160,000 people are expected through the airport today, about 40,000 more than a normal day.
Some people arrived with masks already in hand.
Delay program at SFO started at 8am. About 50 flights impacted, mostly flights along west coast.— Matt Keller (@MattKellerABC7) November 20, 2018
Better than yesterday when ~250 flights were delayed. pic.twitter.com/pBSR4syXBR
"We looked online and they were outrageously priced so I decided to go to the Lowes by us and buy some," said Portland resident Elizabeth O'Malley.
The air quality is expected to improve Wednesday, but the incoming storm may still cause delays.
If you're heading to the airport and want to check on the status of your flight, go here for SFO's Flight Tracker.
Smoke still lingering around SFO this morning. pic.twitter.com/Sei0BcTxmP— Matt Keller (@MattKellerABC7) November 20, 2018