American Airlines said it would cancel another 250 flights Saturday, putting the number of flights nixed by the carrier this week well above 3,000.
The airline said Friday afternoon that Saturday's cancellations will occur mostly in the morning and midday. It expects to have all its MD-80 aircraft fixed, inspected and ready to go by late afternoon.
American is planning on resuming a full schedule late Saturday and "certainly by Sunday."
With more than 3,000 flights canceled this week, American Airlines is still scrambling to accommodate passengers. The airline canceled 595 flights Friday, in addition to the thousands it had canceled since Tuesday.
By Friday morning, more than 225 of the carrier's 300 MD-80 jets were back in service. The airline is rotating the planes back into service once inspectors re-examine wiring, and expects to get the rest of them back in the air by Saturday night.
Delta, Midwest and Alaska airlines also canceled flights this week for inspections, though in smaller numbers than American.
But as the airlines continue to reaccommodate customers, many travelers stranded in the nation's airports are raising the same question: "Why would they come out with a plan to ground all the planes at one time?" asked Sanjay Amin, a traveler trying to get from Chicago to Dallas.
Congress is asking the Federal Aviation Administration the same question.
At a Thursday aviation hearing on Capitol Hill, Sen. John D. Rockefeller IV, D- W.Va., wondered whether the FAA could have avoided mass cancellations had it conducted more frequent and regular compliance checks. He wondered whether the American planes would have been grounded if the news of the uninspected Southwest planes had not become public.
"If this had been identified at another point in time, I believe the outcome would have been the same," said Nicholas Sabatini, the FAA's associate administrator for aviation safety. Sabatini praised the work the FAA has done so far in "extending the safest period in aviation history."
The FAA recently found airlines were 99 percent compliant with safety directives after nearly 2,400 audits at 117 air carriers.
Rockefeller called this week's cancellations "catastrophic economically" and "an embarrassment to the nation."
"This has obviously caused a volcanic disruption which is, in and of itself, unthinkable," he said.
Both House and Senate lawmakers accuse the FAA of having too close a relationship with the industry it regulates — at the expense of airline safety. Echoing the sentiments expressed at last week's House hearing, lawmakers and aviation experts said Thursday that this week's cancellations aren't entirely American's fault, but also the FAA's fault for running a broken system.
"A slew of aircraft groundings indicate that there are problems within the system that are not being addressed," said Tom Brantley, president of Professional Aviation Safety Specialists.
"You don't have to play patty-cake with the airlines to be nice to them," House Transportation and Infrastructure Committee Chairman James L. Oberstar, D-Minn., told ABC News on Thursday. "You do have to oversee that they're doing their job right, especially in an era of outsourced maintenance."
On Thursday afternoon, American's chairman and chief executive Gerard Arpey was apologetic.
"I take full personal responsibility for our being in this situation," Arpey said.
Still, travelers like Jeff Ostrove fill the airports. Ostrove was stuck Thursday morning in Los Angeles on the latest leg of his tortured journey from San Diego to Tortola in the British Virgin Islands.
"We had a flight from San Diego through Dallas-Fort Worth to San Juan [Puerto Rico] down to Tortola, and they called us yesterday morning and told us it was canceled," Ostrove explained.
He was rebooked through Los Angeles, Chicago and San Juan, but then received an e-mail informing him of another cancellation.
"Basically in the middle of the night, 2:30 in the morning, we left San Diego and drove up here, and they are getting us through Miami to San Juan to Tortola," he said.
This week's cancellations came in addition to hundreds of cancellationsin late March. The Federal Aviation Administration called for inspections among all carriers after slapping Southwest Airlines with a $10.2 million fine for failing to adhere to requirements for safety and inspection checks.
All airlines are now beginning phase two of the inspections called for by the FAA, which are slated to be far more extensive than phase one.
Arpey said the FAA maintenance directive currently in question for American's wire bundle inspections is 38 pages long.
Still, cancellations at American on their own are making a tremendous impact. Data released Thursday by the Bureau of Transportation Statistics revealed that in January of this year, American Airlines carried 7.7 million passengers — more international and domestic passengers combined than any other U.S. airline.
"As passengers, we should be glad that the FAA is ensuring that the planes we fly on are safe," Jim Hall, former chairman of the National Transportation Safety Board, said Thursday. "I think the FAA is trying to make a statement, and I think that the message will hopefully be heard by all the airlines, and we won't have to see this repeated by each major carrier in the United States."
ABC News' Zach Wolf contributed to this report.