Shutdown nears an end, but flight delays and cancellations keep piling up, data shows

The crisis hit an agency already under pressure.

With Congress deadlocked, about 13,000 controllers and 50,000 TSA agents are working without pay.

That strain has only deepened as nationwide staffing shortages disrupt air travel, causing tens of thousands of delays and affecting at least 3.2 million passengers, according to airline estimates. 

In Chicago alone, more than 1,400 flights were delayed and nearly 500 canceled on Sunday, according to the aviation tracking website.

Of the four major airlines analyzed - Southwest, United, American and Delta - Southwest logged the most flight delays nationwide this week, while Delta recorded the highest number of cancellations, according to FlightAware data.

On Monday, the aviation tracking website FlightAware reported nearly 3,830 delayed flights and more than 1,650 cancellations within, into or out of the U.S.

As lawmakers work to finalize a deal to reopen the government, aviation officials warn that the effects of the shutdown won't disappear overnight. 

Rebuilding schedules, restoring staffing levels and regaining public confidence could take weeks, a reminder of just how quickly political gridlock can bring the nation's airways to a standstill.