When a major airline needs a pilot to fly planes, they often look to the regional airlines. But when pilots for smaller commuter planes move over to the majors, it's getting harder to find their replacements.

Since 2013, Yuma, Arizona, a largely agricultural region of about 200,000, has seen airline departures drop more than 50 percent. Now, the only flights out go to Phoenix.

The Yuma to Phoenix route is operated by a regional carrier, just like 42 percent of the nation's air service. The smaller airlines are being hurt by pilot retirements and the expansions of bigger carriers. Recent studies predict a shortage of more than 14,000 pilots by 2026.

Lyle Hogg is president of regional carrier Piedmont Airlines, which needs to train and replace as many as 240 pilots a year.

"The pipeline for young aviators is drying up and it should be a national concern," Hogg said.

That's because without enough pilots, flights would have to be canceled or service to some cities stopped. The cost of initial pilot training is almost three times more expensive than it was in the 90s. After a deadly crash in 2009, new pilots are required to fly for 1,500 hours before being eligible for hire.

New hire Corey Cave spent three years and tens of thousands of dollars to log enough hours.

"The cost, it just delayed me a little bit," Cave explained.

Hogg says many of their young pilots have has much as US$300,000 in debt by the time they work for a regional carrier. Piedmont is trying to cut down on that cost by using flight simulators.

"We can simulate all kinds of weather situations, all different malfunctions," Hogg said, "Much better than we can do it in an aircraft and much more safely."

Airline groups have been pushing Congress to change the 1,500 hour rule, but there is resistance to that. To attract pilots, regional airlines have aggressively increased starting pay to about US$60,000. A few years ago, they were closer to US$40,000.