Laura Friedman has commuted up to Northern California for the past six years.

Ms. Friedman, who is from the Los Angeles area, leads the transportation committee in the state assembly. I return to Southern California on Thursdays. There are usually a lot of people on that flight.

Ms. Friedman and many other Californians were left wondering what the disruptions would mean for the airline that has become the mainstay of day-to-day travel in the nation's most populous state.

Southwest is now an essential bridge across the north-south divide in California, where white-collar workers, college students and families have come to rely on the airline the way New Yorkers rely on the Long Island Rail Road.

Southwest is California's busiest airline with 800 flights scheduled on peak days. California's medium-size airports suffered some of the worst cancellation rates in the nation over the past week because Southwest accounts for so much of their traffic.

Henry Harteveldt is an analyst based in San Francisco who covers airlines for Atmosphere Research Group.

A list of canceled and delayed Southwest flights at Los Angeles International Airport on Tuesday. Credit...Kyle Grillot for The New York Times

This year's travel debacle in Texas, Hawaii, Alaska and Florida shows the perils of relying too heavily on planes in an era of climate change, according to analysts and policymakers. Commuters in Texas rely on Southwest to travel across the state and last week's disruption stranded fliers from El Paso to Houston

The state of California does not need the railway that was originally sold as a link between the San Francisco Bay Area and Southern California because of cheap Southwest flights. A high-speed rail plan was defeated by the airline decades ago.

More than 2,900 Southwest flights were canceled across the country on Monday, with thousands more scrapped daily for the next three days.

Many Southwest passengers were told they might be stranded for a long time. At one point this week, the only one-way ticket on short notice from Sacramento to Los Angeles was a first-class seat on Delta for nearly $700.

It usually takes six to nine hours to drive from Northern to Southern California, but some people decided to take the rental car offices.

The airline said in a statement that it would resume its full flight schedule on Friday after stabilizing its operations. By midday Thursday, only a few dozen flights had been canceled.

Customers will not be there just because the flights are running. Southwest's brand has been damaged due to this event.

In California, where the Texas-based airline operates more flights than anywhere else in the country, the brand has become more important. Southwest had more California travelers to, from and within California than any other airline, according to the airline.

Southwest began as a way to ferry passengers between Texas cities in an era when airlines tried to keep their travel within state lines to avoid federal oversight and costs. One of the nation's four largest carriers serves routes across the country. It used to be known for its low fares, abundant flights, and sometimes musical flight attendants.

Southwest dominates air travel at seven of California's 10 busiest airports, even though it is a minor player on the busiest route. The airline is the largest seller of seats for sale on flights within California, according to Mike Arnot.

Southwest is California’s busiest airline, with more than 800 flights on some days, many of which ferry residents between Northern and Southern California.Credit...Kyle Grillot for The New York Times

Southwest accounted for 80 percent of traffic at Oakland International Airport and 63 percent at San Jose International Airport in the past year.

It is a part of the culture. It's spoofed by Hollywood. Jimmy checks it out in his monologues. Gray Davis, the governor of California who was recalled by voters in 2003 and replaced by the actor Arnold Schwarzenegger, used to frequent Southwest Airlines. Private jets were used by Mr.

She flies Southwest for work twice a week to Southern California. She said that Southwest offers so many flights between California airports that she can hop on an earlier flight if she finishes court early or if the trial location changes at the last minute.

She said she couldn't think of another airline she could do it on. People who do what I do have private planes. They don't fly any other airlines because nothing else will give you the flexibility.

The Southwest flights between the Bay Area and the Los Angeles region were full of people like her.

A lot of people commute between Northern and Southern California on these flights.

Lobbyists booking flights at the beginning or end of the week in the hopes of sitting next to a lawmaker are one of the changes that have evolved around their schedules. Half of the traffic at the airport is Southwest.

Tom Umberg is a Democratic state senator. He has commuted to the state capital from Orange County for many years and says the airline is the only viable option for his 450 mile commute.

If she couldn't catch her usual Southwest flight from Burbank, Ms. Friedman would have to take a seven-hour drive to get there.

She said she enjoyed it. Everyone is eating the same Chex Mix or whatever it is for breakfast and there is no first class.

Ms. Friedman said she would usually sit with a Republican senator from another part of Los Angeles County, and use the flight to catch up on work, at least when the plane wasn't full of school groups. The recent episode has been sobering.

She said that the Legislature needs to do more to support the rail network. Assuming that she makes it there, she has a couple of bills that she wants to pay.

David Montgomery reported from Austin.