Six skywriting planes were used in the anti-Trump stunt above the annual Rose Parade in Pasadena, CNN said.
Other messages hitting out at Trump, the frontrunner for the Republican nomination for the White House, included: “Anybody but Trump,” “Trump loves to hate” and “Trump is delusional.”
It was not immediately clear who was behind the protest, images of which were posted on social media.
Trump, whose controversial run for the White House has seen him call for a ban on Muslims entering the United States, did not make any immediate response.
The billionaire real-estate tycoon and reality TV star, who has said that Mexico is sending rapists and other criminals into the US, greeted the 2016 election year by proclaiming on Facebook: “2015 was a very special year, and I am grateful for your support!
“We are making history together! The silent majority is no longer silent.”