Spirit Airlines, an impish upstart that shook the industry with its irreverent ads and deep discount fares, announced Saturday that it has gone out of business after 34 years.

The ultralow cost airline that once operated hundreds of daily flights on its bright yellow planes and employed about 17,000 people said it had "started an orderly wind-down of our operations, effective immediately."

The airline said on its website that all flights have been canceled and customer service is no longer available.

"We are proud of the impact of our ultra-low-cost model on the industry over the last 34 years and had hoped to serve our guests for many years to come," the announcement said.

U.S. Transportation Secretary Sean Duffy said Saturday that Spirit had a reserve fund set up for customers who bought directly from the airline to get refunds. People who bought from third-party vendors like travel agents would have to seek refunds from them. He had a stark message for people flying with Spirit.

"If you have a flight scheduled with Spirit Airlines, don't show up at the airport. There will be no one here to assist you," Duffy said.

He said United, Delta, JetBlue and Southwest were offering $200 one-way flights for people who could confirm that they had Spirit confirmation numbers and proof of purchase for a limited time. Duffy also said other airlines would help with Spirit employees who might be stranded as well as offering them a preferential application process as they look for work.

Spirit said in a statement it was working to get more than 1,300 crew to their home bases and that the final Spirit flight landed at Dallas Forth Worth International Airport from Detroit Metropolitan Airport.

The company advised customers that they could expect refunds but there would be no help in booking travel on other airlines.

Five Spirit flights were still showing as "on time" on Saturday morning on the departure board in Atlanta, one of the airline's smaller stations.

A trickle of passengers who hadn't heard the news were still showing up, including Joshua Sigler, who had bought a ticket Friday for a flight Saturday to Miami.

"I'm just going to go back home," said Sigler, who didn't try to take advantage of deals some other airlines were offering to displaced Spirit passengers.

He said he had gotten no communication from Spirit, which he had flown multiple times in the past. "They get you there," he said of past flights. "It was cheap."

Former Spirit flight attendant Freddy Peterson was on a Spirit flight from Detroit that arrived in Newark around 11 p.m. Friday. He said that despite rumors flying on social media Friday, things seemed kind of normal, with more than 200 passengers on the plane.

"All our aircraft were packed," he said.

Peterson, 60, said he set his alarm clock for 3 a.m. Saturday to check the company website at the hour of the rumored shutdown.

"I said, OK, well, since all this going on, they said Spirit is supposed to close at 3, I'm going to bed. I set my alarm clock for 3 o'clock, went onto the website and it said, 'Spirit flights have been canceled,'" Peterson said.

He said Delta Air Lines brought him and another flight attendant back to Atlanta on Saturday morning, with Peterson leaving from there to drive to his home in Shellman in southwest Georgia.

"I'll probably do my boo-hoo crying and all that other stuff once I get in the car."

Peterson said he had been a flight attendant with Spirit for 10 years and the company has "done wonders for me." He said the airline's reputation for bargain basement chaos was largely undeserved, but he did fault management for not communicating with the employees in the closing days, saying a promised employee town hall was canceled.