Did Croatia Airlines install a system for releasing chemtrails from its planes without the knowledge of the public? No, that's not true: The 2015 article on which the claim is based is satirical, with a disclaimer at the end. Croatia Airlines denied the claim in a written statement in 2020.
The claim appeared in a video (archived here) on TikTok on February 4, 2024. It began (translated from Croatian to English by Lead Stories staff):
Croatia Airlines installed a Chemtrails release system on its planes without the knowledge of the public
This is what the post looked like on TikTok at the time of writing:
(Source: TikTok screenshot taken on Tue Feb 6 08:36:43 2024 UTC)
The video shows a screenshot of an article headline (archived here), posted by an online portal Dubrovački Dnevnik (Dubrovnik News) on July 26, 2015. The article includes satirical claims such as the following (as translated):
According to the source, CA made losses in the amount of HRK 488 million until 2012, and then, together with the Japanese-American consortium for chemtrails, Poshipu Limited, entered the system as a member of the Star Alliance group and already in 2013, made a profit of 722 thousand kuna, and when it started spraying Chemtrails on all planes throughout 2013, they recorded a profit of more than 7.5 million kuna.
And (as translated):
However, from the Union of Cabin Crew, they unofficially say that the night before, they inhaled so much Chemtrails that they didn't know where their heads were and where the cockpit was.
At the end of the article is a disclaimer in brackets (as translated):
(This is satirical content of Dubrovnik News :) )
The same news portal posted another article on November 26, 2020, titled "THEY USED THE DUBROVNIK NEWS' SATIRE Crazy theory denied by Croatia Airlines: We don't disperse chemtrails!" (archived here). The article reported that their satirical claim was spreading on social media. It also featured a statement from Croatia Airlines (as translated):
The information that you provided is completely incorrect and unfounded.