It's been a chaotic summer for air travel.
Airlines have delayed and canceled tens of thousands of flights in recent weeks, even during this July 4th weekend.
NPR's transportation correspondent, David Schaper, joins us now.
David, so first of all, tell us how busy the skies are right now.
I mean, is air travel demand back to where it was before the pandemic?
Well, not quite, but it is getting pretty close. The skies have been very busy this summer.
And over the last week or so, the number of people flying has been getting to near 95% of prepandemic levels.
Joe Schwieterman is an airline industry expert at Chicago's DePaul University.
He's been tracking the number of people flying relative to the number of available seats.
And he says the big problem right now is that airlines have far fewer flights than they did before the pandemic.
So nearly every flight right now is completely full.
When you just take a large plane of 250 people and you cancel that flight and have to find, you know, standby seats or empty seats for those people on a weekend that doesn't really have a low point, it puts the airlines in a really tough spot.
Because the airlines will have a tough time rebooking passengers because they have so few seats available.
So why are the airlines canceling so many flights?
I mean, were they unprepared for this?
How would they not know that after two years that we wouldn't want to go out in the world again and fly?
I mean, we've heard about staffing shortages, especially among pilots, and weather. I mean, is that it?
Yeah. You know, the airlines were preparing for a big surge in people flying again, but they were overly ambitious and added more flights to their summer schedules than they could staff because of a shortage of pilots and really every other kind of employee, from mechanics to flight attendants, too.
And they've since cut a lot of flights from their schedules, but they're still stretched very thin.
Pilots say they're working record amounts of overtime, but industry experts say the airlines still have very little wiggle room to stay on track when things go wrong, like bad weather.
Bill McGee is an aviation consumer advocate who used to work in airline operations.
I'm not speaking hyperbolically, but I can tell you, David, that this is the worst I've ever seen in the 37 years I've been around this industry.
McGee says the airlines know that they're not going to be able to operate all the flights that they've scheduled, but they're often not canceling until the very last minute.
And one measure of just how awful it is - passenger complaints about airlines to the DOT so far this year are up a whopping 300% over 2019.
That sounds like a lot. Now, you said staffing shortages are only part of the problem leading to those huge number of flight delays and cancellations.
What else is going wrong?
Well, you know, the airlines are also short on planes.
They haven't returned to service all of those that they parked during the pandemic.
But the airlines point to something else.
They blame many of the cancellations and delays on air traffic control problems.
They say one key air traffic control center in Jacksonville, Fla., was understaffed recently for 27 of 30 days.
And other centers have been short staffed, too.
The FAA acknowledges some staffing shortfalls and say they're being addressed.
But the agency fired back at the airlines, criticizing them for misusing government aid that was intended to prevent short staffing at the airlines.
A spokesman says, quote, "People expect when they buy an airline ticket that they're going to get where they need to go.
After receiving $54 billion in pandemic relief to help save the airlines from mass layoffs and bankruptcy, the American people deserve to have their expectations met."