(KDVR) — Hundreds of Southwest Airlines customers have been left with canceled or delayed flights as the airline continues to recover from “operational challenges” that marred the holiday weekend for many.

Southwest scrubbed thousands of flights again Tuesday in the aftermath of the massive winter storm that wrecked Christmas travel plans across the U.S. An additional 2,500 flights have been scrubbed for Wednesday, and nearly 1,400 for Thursday. The federal government has already said it will investigate why the company lagged so far behind other carriers.

The problem, according to Southwest, is the areas that saw the worst weather are the most dependent on the airline.

“We were fully staffed and prepared for the approaching holiday weekend when the severe weather swept across the continent, where Southwest is the largest carrier in 23 of the top 25 travel markets in the U.S.,” the airline said.

Southwest confirmed that while it works “to recover our operation,” it will be flying only about one-third of its schedule “for the next several days.” In a statement released Tuesday evening, CEO Bob Jordan said they hope to have their schedule “back on track before next week.”

“The tools we use to recover from disruption serve us well 99 percent of the time; but clearly, we need to double down on our already existing plans to upgrade systems for these extreme circumstances so that we never again face what’s happening right now,” Jordan added while apologizing for the widespread problems with Southwest flights.

So what can you do if your Southwest flight was canceled?

Nexstar’s KDVR reached out to the airline and got this statement back:

“We are re-accommodating as many customers as possible, based on available space, whose itineraries have been disrupted. Those whose flights have been canceled may request a full refund or receive a flight credit, which does not expire,” said Chris Perry with Southwest Airlines.

Kurt Ebenhoch, a consumer travel advocate and former airline executive, told the Associated Press that travelers are eligible for a refund, not just vouchers for future travel. If you do take a voucher, make sure you inquire about blackout dates and other restrictions on its use.

Southwest also addressed what customers can do if their luggage is missing.

“Information for customers with lost baggage is here. Customers can also speak with a representative at the baggage service office in an airport where we operate or contact Southwest customer service,” Perry said.

The company also encouraged affected passengers to check its travel disruption information. Southwest notes all customers traveling through next Monday can rebook their flight within 30 days of their original flight day between the original cities without paying additional charges.

If you’ve had a Southwest flight canceled or delayed — since Christmas Eve and until January 2 — and had to pay for a hotel, rental car, alternate transportation, or food, you can submit a request for reimbursement. Requests for reimbursement can be filed on Southwest’s website here.

“On the other side of this, we’ll work to make things right for those we’ve let down, including our employees,” Southwest said Tuesday. “We recognize falling short and sincerely apologize.”

The Associated Press and Nexstar Media Wire’s Alix Martichoux contributed to this report.