Delta Airline pilots conducted informational picketing Friday at eight airports around the United States to protest stalled contract negotiations. Pilots picketed at eight airports where Delta has major operations, including Minneapolis, Detroit, Los Angeles, New York LaGuardia, Seattle, Salt Lake City, Atlanta and Cincinnati.

Under conditions in which the airline is enjoying booming profits, the pilots are seeking to recoup massive concessions surrendered during Delta’s 2005 bankruptcy, which included average pay cuts in excess of 40 percent. Delta recorded pre-tax income of $1.56 billion in the first quarter of 2016, triple the amount for the same period last year. It made $4.5 billion in 2015.

The pilots’ contract became amendable December 31, 2015, but contract talks began 10 months earlier. The pilots are seeking a 40 percent compounded pay increase while maintaining their current level of profit sharing Starting pilots at Delta earn some $68,000 a year according to one report. That is less, not counting profit sharing, than pilots at United Continental and American, as well as at cargo shippers Fedex and United Parcel Service.

Delta and the Air Line Pilots Association have been meeting with the US National Mediation Board since March. Under terms of the Railway Labor Act, pilots are barred from striking without first navigating a maze of legal obstacles, and Delta pilots are only at the beginning of the process.

Pilots rejected an ALPA-recommended tentative agreement in July 2015 by a 65 percent margin, with about 85 percent of Delta’s 12,800 pilots voting. The proposal would have reduced profit sharing and imposed a new, draconian, sick leave policy as well as work-rule changes. It provided for an inadequate wage increase of an immediate 8 percent followed by 6 percent, 3 percent and 3 percent over the next three years.

Following the rejection vote, the ALPA master executive chairman, Captain Mike Donatelli, submitted his resignation. He was replaced by Captain John Malone, a Delta pilot based in Atlanta.

At Detroit Metro Airport, police forced protesting pilots to picket behind metal barricades away from the front entrance to the Delta terminal. About 1,500 Delta pilots are based in Detroit, a regional hub. “Delta Airlines is now the most profitable airline in the history of the industry,” said Captain Mark McClain, a 33-year veteran Delta pilot and an ALPA spokesman in Detroit.

“What we want is a restoration of concessions that recognizes our contribution.

“This job requires a university degree and an FAA rating, which takes an additional two years. Most of the pilots here have eight to 10 years previous experience before they are hired by Delta.”

Asked about the proposal pilots rejected in 2015, McClain replied, “The proposal last year reduced profit sharing. It basically took money out of one pocket and put it in another. We were funding our own pay raises. When a contract is voted down 65-35 percent there is a disconnect.”

“The market rate for pilots has risen,” he said referring to the current shortage of experienced pilots. “We are looking for a contract that recognizes our contribution.”

Captain Tim Hooey, a pilot with 28 years in the cockpit and also an ALPA representative, added, “We are substantially below our other peers right now. We are 40 percent below what we were in 2004. A recent FEC filing showed that Delta was paying big dividends and handing big raises to management, but pilots have gotten no rewards.”

Currently there are tens of thousands of airline workers facing contract expirations or working without a contract. This includes pilots at Southwest Air and United Parcel Service. Pilots at Fedex recently concluded contract negotiations.

In February, 9,000 mechanics and maintenance workers at United Continental Holdings voted to reject a sellout contract negotiated by the Teamsters by a 93 percent margin. The contract would have provided a 25 percent wage increase, but this would have been offset by a raft of concessions including the creation of a new “B” scale for new hires, who would have earned drastically less than veterans. It also imposed higher medical costs. Continental pilots are currently working under a two-year contract extension.

Meanwhile, United Continental announced Friday it was close to a tentative agreement with 25,000 flight attendants over terms of a new contract after three years of negotiations. It would be the first joint contract agreement since United and Continental merged in 2010.

The vote by United Continental mechanics followed a contract rejection vote by Southwest Airline pilots last November. Southwest Airline flight attendants rejected a contract proposal last July that included a 3 percent pay increase along with significant concessions in work rules.

Over the past several decades there has been a continuing assault on airline workers, including massive wage cuts and the destruction of pensions and working conditions aided and abetted by the unions. This has continued even as airline profits rebounded, in part because of the plunging price of oil, from which jet fuel is extracted. The year 2015 was the most profitable for the airline industry since the start of deregulation in 1978.

Pilots internationally continue to resist the relentless pressure by the airlines for further cost cutting. Air France workers threatened a four-day strike this week over changes to work rules, before management suspended its cost cutting plan.

EasyJet pilots based in Amsterdam struck Friday over sick pay, rest time and pensions. They are currently working under personal contracts, but demand a collective bargaining agreement. And earlier this month Scandinavian Airlines pilots struck over a wage increase.

The United States appears to be at the beginning of an airline pilot shortage, as airlines expand operations and a wave of retirements is expected as pilots reach the mandatory retirement age of 65. Entry to the profession is difficult. It requires rigorous training and numerous certifications. Meeting the 250-hour minimum flight time requirement can take at least six months and cost up to $100,000, which most pilots are forced to pay out of pocket. New federal regulations impose even more stringent requirements.

The military, which previously provided a large portion of airline pilots, now accounts for only about 30 percent of new airline pilots. This pool is likely to shrink as the military offers incentives for pilots to stay in the service longer.