Oscar Munoz, CEO of United Airlines, on the changing industry and customer expectations

United Airlines CEO Oscar Munoz thinks airlines are reaching a breaking point with shrinking seat sizes.

"I think we are nearing a point certainly that we can't do that anymore," he told ABC News' Senior Transportation Correspondent David Kerley.

Munoz acknowledged having to stay competitive with peers and match many of their moves, but he admitted passengers may have had enough.

Another common complaint? Wi-Fi. Why does it so often not work on flights?

"It's complicated technology," he said. "We will fix that, and, frankly, we would stop a lot of our growth if we could just stop and find the right provider and get that done. That's how important Wi-Fi is to us and to our customers."

Munoz recognizes the changing culture of air travel -- an experience that for many transformed from an exciting experience to a painstaking one. He hopes that will change soon.

"It's become so stressful," he said, "from when you leave, wherever you live, to get into traffic, to find a parking spot, to get through security."

"Frankly," Munoz added, "by the time you sit on one of our aircraft ... you're just pissed at the world," and improving the flying experience won't ultimately depend on "what coffee or cookie I give you."

This interview is part of ABC News' Up To Speed series with David Kerley and took place before the grounding of the Boeing 737 MAX in the United States .