With a pilot shortage looming for U.S. airlines, three subsidiaries of American Airlines announced Monday that they will offer $15,000 signing bonuses to newly minted pilots.

Envoy Air (formerly American Eagle), Piedmont and PSA Airlines, which operate short-haul or "express" flights for American, are offering signing bonuses to lure new aviators at a time many senior pilots are near the mandatory retirement age of 65, and it's become harder to be a pilot.

New federal pilot-rest rules and tougher qualification standards since 2013 require commercial co-pilots, or first officers, to have 1,500 hours of minimum flight experience, up from 250.

Fewer young people are opting for cockpit jobs because of the cost of training and low entry pay – $22,500 to $26,000 to start at the regional airlines, which operate half the nation's scheduled flights.

In Philadelphia, 65 percent of 470 daily American departing flights are operated by regional carriers, including Republic and Air Wisconsin, that fly under the American banner.

Pilots who make it to the major airlines earn substantially more, $200,000 to $300,000 a year, for a captain on international routes.

The Federal Aviation Administration's new hourly requirements have made it more expensive to become a pilot – "a minimum $150,000" for a four-year college degree, training, and flight hours, said Dennis Tajer, spokesman for American's Allied Pilots Association.

"If you just do the minimum to get licensed, I'm certain that you are well into six figures," Tajer said. "So you may come out with the same debt as an attorney."

Second-year pilot pay at a regional airline is about $32,000 and $36,000 in the third year, Tajer said.

After the September 2001 terror attacks and subsequent airline bankruptcies and restructurings, "you created an environment that caused people to flee, vs. run to, the profession," Tajer said. "It has resulted in an epidemic of pilot shortages" that already affects smaller communities that depend on regional aircraft for air travel.

While the big airlines - United, American, and Delta - have plenty of pilots, their main source of aviators are the regional carriers.

In addition to signing bonuses, the regionals have promised a path to employment at American Airlines, which operates 70 percent of flights in Philadelphia.

"Envoy pilots currently make up half of every American Airlines new hire class - in fact, nearly two thirds of American new hires since 2010 started their career at Envoy," said Ric Wilson, vice president of flight operations.

Salisbury, Md.-based Piedmont promised new hires "a very quick upgrade" to captain "and a guaranteed job at American Airlines in a few years," said president and CEO Lyle Hogg.

Piedmont said it plans to hire more than 200 pilots this year, and will hold information sessions and interviews at Philadelphia International Airport on June 17, at the Newark Airport Marriott on June 23, and at New York's JFK Airport Courtyard Marriott on June 24.