An employment dispute between Russia's largest airline and an outspoken union leader has highlighted a sharpening confrontation between pilots and Russia's air carriers over how to deal with a chronic shortage of qualified fliers.

Aeroflot pilot Igor Deldyuzhov, who also heads the Sheremetyevo Cockpit Personnel Association, was fired by the airline in March 2012 but won an unfair dismissal case in September.

A Moscow Court on Monday postponed a decision on Aeroflot's appeal of the ruling, extending a bitter dispute that trade union officials have described as a "war."

Depending on whom you believe, Deldyuzhov's mistake was either failing to pass a pilot's exam or adhering too conscientiously to air safety rules.

But the dispute really seems to go to the heart of a crisis facing Russia's aviation sector: What do you do when you are running out of pilots?

Deldyuzhov says he was fired for violating Aeroflot's internal procedures by enlisting a third pilot on a long-haul Moscow to Tokyo flight in late 2011, a measure his union argues was necessary to ensure compliance with a Transportation Ministry regulation dictating the amount of time pilots can work without a break.

Deldyuzhov was unavailable for comment Monday, but Sheremetyevo Cockpit Association spokesman Igor Obodkov said he believed the airline had taken advantage of this violation of Aeroflot's rules to punish him for heading the union, which claims to include 850 of Aeroflot's approximately 1,500 pilots among its membership.

"We've got a serious war on with Aeroflot. This isn't about any alleged violation of procedure. It's because the union is strongly fighting for the interests of its members," Obodkov said.

Aeroflot flatly denied both the accusations of union-busting and the association's account of Deldyuzhov's dismissal.

"The main reason for the dismissal of Mr. Deldyuzhov was he failed to pass a pilot's qualification procedure. If an employee is violating the rules and regulations of the company, he cannot guarantee the safety of passengers," an Aeroflot spokesman said by telephone.

But the airline has made no secret of its irritation at the trade unionist. The spokesman said the company had previous issues with Deldyuzhov's breaches of confidentiality when he discussed internal Aeroflot affairs in public.

"Unfortunately, under Russian law, a company has no way of firing staff for damage to reputation. And we believe he damaged our reputation because while he was an employee, he accused the company of a lack of safety measures," the Aeroflot spokesman said.

In fact, as the spokesman said, Aeroflot is rated the safest airline in Russia.

Independent industry watchers say it is difficult to untangle exactly who is right and wrong.

"It's one of those cases where when Deldyuzhov explains his position, you think he's right, and when Aeroflot explains their position, you think they're right," said Roman Gusarov, editor in chief of an Avia.ru, an industry website.

But the case goes to the heart of a brewing confrontation between air crew unions and Russia's largest airlines over pay and conditions.

Kobodkov said the root of the dispute is attempts by Aeroflot and other airlines to water down employment laws to make pilots fly longer hours and take shorter vacations and allow airlines to hire foreign pilots.

"It's because we are fighting strongly for our members' interests," he said.

Russian pilots still enjoy comparatively strong benefits compared with their Western peers, including about 70 days of vacation a year, said Gusarov.

Aeroflot and other major airlines argue that these protections — many of them dating from the Soviet era — make them uncompetitive with Western rivals.

From the airlines' point of view, it is a problem that is only exacerbated by a shortage of qualified fliers.

"It's not just that we're not training enough people. It's that the Russian air travel sector is growing at a rate of 25 to 30 percent in terms of passengers carried every year," Gusarov said. "You just can't churn out enough pilots to meet that demand."

Dmitry Stolyarov, first deputy CEO of Transaero, said in October that there are about 14,200 qualified pilots working in Russia, and about 700 leave the industry annually.

Combined with the growth in demand for air travel, that is leading to a shortage of about 2,100 people a year, he said.

There have been some minor changes. On Jan. 30, the High Court granted Aeroflot the right to calculate a pilot's additional vacation on calendar days, not working days.

But the court turned down a request to strike down Transportation Ministry Decree No. 50, a Soviet-era law that grants flight crews extra vacation days because of the "special nature" of their work.

Aeroflot had argued that the decree, which was issued in 1986, was unsuited to modern conditions and contradicted the 2002 Labor Code.

Aeroflot's contracts with pilots grants them 40 additional calendar days of vacation on top of the 28 calendar days stipulated in the Labor Code. Decree No. 50 grants vacation on working days, Gazeta.ru reported.

The unions argue that the reforms would place passengers in danger. The Sheremetyevo Cockpit Personnel Association says there were no fewer than 22 cases of loss of radio contact with aircraft, which were "most likely" the result of fatigued pilots falling asleep in the cockpit in 2011.

And Obodkov said the idea that Russian pilots are relatively well off is a myth.

"Aeroflot pilots fly 900 hours a year on average. At Delta, it is 750," he said.

But the staff shortage is real, and it is posing a problem for airlines and potentially putting dangerous strain on over-worked fliers, Gusarev said.

One answer floated by the Transportation Ministry and several airlines, including Aeroflot, Transaero and S7, is to allow Russian carriers to hire foreign pilots to pick up the slack.

The idea has been included in the ministry's road map for transportation development and could be on the books by the end of the year.

But the move is fiercely opposed by pilots' associations, which have warned that it could allow airlines to hire poorly qualified but cheaper pilots from other former Soviet republics.

The Sheremetyevo Cockpit Personnel Association, which Deldyuzhov heads, even produced a pamphlet warning of "Gastarbeiter in the sky."

"As a completely neutral observer, I would guess it will be resolved in the interests of the airlines," Gusarov said.

That's partly because the state is the majority shareholder in Aeroflot and partly because "everyone understands it is the only way out" of the current situation, he added.

"It's no silver bullet. Not every pilot is going to be able to just move to Russia and start working here, and Western airlines are also growing rapidly, so the competition for qualified flight crews is not just limited to Russia. But it is probably the only thing to do," Gusarov said.

Deldyuzhov is still employed at Aeroflot and is completing the exams he was originally fired for not taking, but it is premature to say whether he will be allowed to keep his job if he passes the tests, the Aeroflot spokesman said.

The Moscow City Court will reconvene on Feb. 12, when a decision is expected, a union spokesman said by telephone Monday.