The break-up comes as US carriers, including American, have been urging the USA government to take action against three Middle Eastern carriers - Etihad, Qatar and Emirates - alleged to have received billions of dollars in subsidies from their home governments.
Qatar Airways CEO Akbar Al Baker is coming under fire from both flight attendants and pilots after he was shown on camera bragging about hiring young women to be flight attendants, while simultaneously mocking rivals for employing "grandmothers".
Etihad said American Airlines' decision is "anti-competitive and anti-consumer", and would limit consumer choices and increase prices for travelers to and from the United States, said the report, quoting an Etihad statement.
The comments came amid an intensifying feud between Qatar Airways and American, which began last month with the disclosure that the Arabian Gulf carrier wanted to buy a stake of as much as 10 per cent in the USA company.
The latest casualty is a marketing deal between the two companies, known as a codeshare, which American Airlines now says it will end because of a longstanding dispute over whether Persian Gulf carriers use government subsidies to compete unfairly.
Baker and Qatar Airways have not responded to the massive condemnation.
Etihad said that it is "disappointed with the decision".
The Middle East carriers, who fly to the U.S. under Open Skies agreements, strongly deny the claims. It sent the notifications on June 29 in protest of what it and the other major USA carriers characterize as illegal subsidies from the governments of Qatar and the United Arab Emirates to the respective OneWorld alliance partners.
The feud between American Airlines Group Inc and Qatar Airways Ltd keeps escalating.
American said in a regulatory filing that Qatar has filed a new notice of its intent to buy American shares.
American Airlines and other dominant USA aviation companies have accused Etihad, other consumer and business groups of relevant air transport agreements violations.
The carrier plans to launch services to 25 new destination throughout 2017-2018, including to Canberra in Australia; Chiang Mai in Thailand; Las Vegas and San Francisco in the US; Rio de Janeiro in Brazil; and Santiago in Chile.