Spectators at the Rose Parade in California were distracted from the floats and flowers when anti-Donald Trump skywriting appeared over the annual California event Friday.
Photos on social media showed the messages in the sky that said things like: "America is Great! Trump is Disgusting," "Anybody but Trump" and "Iowans Dump Trump."
Iowa's Hawkeyes were set to play against Stanford University's Cardinals, and the Iowa caucuses are just one month away.
It wasn't immediately clear who commissioned the skywriting, but aerial advertising company AirSign took credit for the handiwork on Twitter, and liberally retweeted photos from people who were fans of the stunt.
Trump remains a frontrunner in the GOP race, despite being criticized for inflammatory remarks.
A spokeswoman for Trump's campaign did not immediately respond to a request for comment from NBC News.