The continuing decline of Italy's flag carrier, Alitalia, is not an unfamiliar process to the world of U.S. commercial aviation.

Like the slow descents of Eastern, Pan Am and TWA during the 1980s and 1990s, it is an emotional process -- for its home country, employees, and customers -- but one that is unlikely to have much impact on global aviation, with one exception: The United Arab Emirates carrier Etihad Airways, based in Abu Dhabi, has been a major investor in Alitalia, at one time raising hopes that its financial and management resources might be sufficient to rescue the troubled carrier.

Alitalia filed for bankruptcy protection on May 2.

On Tuesday, Alitalia found it necessary to remind travel agents that normal operations continue. 

"Alitalia reiterates that its operations and flights have neither been nor will be affected by the current company situation," the carrier said in an email to travel agents.

"All flights and services will continue to take place as planned and without any changes," the carrier said. "Tickets already purchased are therefore valid."

Like Eastern, Pan Am and TWA, Alitalia lost markets to more efficient competitors; attracted outside investors who initially promised salvation, and exposed conflicts in employees who simultaneously valued and doubted the carrier.

"Maybe the Pan Am {comparison} is the most relevant," said travel writer Joe Brancatelli. "Alitalia has been the Italian 'chosen instrument,''' just as Pan Am at one time was the primary symbol of U.S. international air service.

Alitalia "has been pecked to death by newbies that didn't have the {restrictions}," just as Pan Am's death reflected a government policy to restrict its domestic network while awarding new trans-Atlantic routes to its competitors, Brancatelli said.

Alitalia has just 1.5% of daily trans-Atlantic seats, so "we don't view Alitalia's bankruptcy as likely to impact aggregate Atlantic supply trends, even in the event of an eventual cessation of service," JPMorgan analyst Jamie Baker wrote recently.

However, Baker seemed to recall the early 1990s, when the Eastern bankruptcy resulted in dramatic fare reductions that pressured all U.S. carriers.

"Financially beleaguered airlines often resort to aggressive discounting in order to cull the confidence of passengers," Baker wrote. "This may pose both a short-term risk and a long-term positive; weaker potential pricing whilst Alitalia seeks a solution, positive potential pricing in the event it vacates the market."

For the big three U.S. carriers, the trans-Atlantic has been a difficult region due primarily to capacity growth by low-cost carriers led by Norwegian Air.

Alitalia is a member of Skyteam and of a trans-Atlantic joint venture that includes Delta (DAL) - Get Report and AirFrance/KLM. According to the Sydney, Australia-based CAPA Centre for Aviation, "Alitalia has not been happy with its membership in the JV, which it views as constraining its ability to expand its network to North America.

"For its part, Delta has often given the impression that it merely tolerates Alitalia in SkyTeam," according to CAPA's paper on Alitalia. "Delta may prefer not to see Alitalia disappear, but it is unlikely that it would feel strongly enough about the strategic imperative to put hard cash into its Italian partner."

In the first quarter, Delta's trans-Atlantic revenue per available seat mile fell 0.5%. "We are offsetting some of the pressure from industry capacity {growth} and currency with a strategy of leveraging our strong joint venture positions in Europe and growing U.S. point of sale volumes," said Delta President Glen Hauenstein on the carrier's first-quarter earnings call. He made no mention of Alitalia.

The biggest beneficiary of an Alitalia shutdown would be Ryanair, "in light of its leading market position in Italy alongside Alitalia," JPMorgan's Baker wrote. "OAG data currently suggests 5.8% {estimated} 2017 capacity expansion in Europe would be trimmed to 4.4% absent Alitalia," Baker said.

In 2014, Etihad paid $565 million to buy 49% of Alitalia. Etihad sought to turn Alitalia around by cutting unprofitable domestic routes, overhauling the aging fleet and retraining employees.

Alitalia's demise appears to demonstrate a hazard of Etihad's strategy to seek global diversification by investing in partners. Etihad also invested about $2.4 billion in Air Berlin, another troubled European airline.

"We announced earlier this year that we were reviewing our airline equity investments even as we remain committed to the strategy of partnership, and we are continuing with that process," Etihad said, in a prepared statement.

However, "What has happened at Alitalia does not affect how we view any of our other equity investments," the carrier said.

The Alitalia fleet includes 76 narrowbody Airbus A320 family aircraft, 14 Airbus A330s and 12 Boeing 777s.

Alitalia has no pending orders with Airbus or Boeing, so its demise would not impact the new aircraft market.

As for used aircraft, "If Alitalia is liquidated, I'd expect perhaps United (UAL) - Get Report to swoop in on some of the A319s, the younger ones," said aerospace consultant Scott Hamilton. "There are some attractive A320s. The A321s are older, probably not especially attractive.

"Twelve of the A330s are 10 years or younger, but they are the less popular -200s, not the -300s," he said. The Boeing 777-200s "date to 2002 and are generally undesirable on the second-hand market. Some bottom feeders (like Delta) may pick some up, but most will probably go to the junk yard.

"Overall, I don't see anything that will move the needle on supply and demand," Hamilton said. He also wondered, "Although it is currently said there won't be a bailout, will this in fact be true? Will the government really let its flag carrier disappear? "

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.