Advertising and auto racing go hand in hand, as car sponsorships financially fuel the efforts of race teams, and some racing leagues have become increasingly selective about what sort of advertising and sponsorships are permissible.

The IndyCar series has reportedly rejected a request from an unnamed team to promote the 2024 candidacies of former President Donald Trump and independent Robert F. Kennedy Jr., according to TheBlaze.

That dual advertisement for Trump and RFK Jr., had it been approved, would have appeared during next month's Indy 500 race, arguably one of the biggest and most-watched sporting events of the year.

IndyCar Series rejects political ads and sponsorships

Racer reported last week that an unidentified entry in the May 26 Indianapolis 500 event had filed a request to promote both former President Trump and RFK Jr. on its car, but that request was denied and the unnamed team was told to find "more traditional motor racing sponsors" ahead of the big race.

A spokesperson for the IndyCar Series told the outlet, "IndyCar does not approve sponsorships associated with elected officials, candidates for political office, or political action committees."

Racer noted that with roughly 300,000 fans in the stands and millions more watching from home, the Indy 500 is a hugely lucrative event for advertisers and sponsors.

Yet, given the "charged and often divisive spirit of politics," the racing league appears to have opted against the risk of "appeasing half of the crowd and viewing audience" while "driving away the other half."

Scheduled Trump appearance at March IndyCar event canceled at last moment

The Racer article also revealed another mysterious rejection of former President Trump involving the IndyCar Series, as he was reportedly invited to give the command to start engines at a special race event in March, only for that scheduled appearance to be canceled at the last moment.

The leadership of The Thermal Club in California had reportedly arranged for Trump to appear at the March 24 "$1 Million Challenge" race and be part of the TV broadcast as well as give the famed command for drivers to begin the event.

However, those plans were reportedly scrapped by the league for "unknown reasons" the night before the race was held.

Trump's name has appeared on cars in NASCAR races

TheBlaze noted that then-President Trump famously declared, "Gentlemen, start your engines" at the Daytona 500 race that kicks off NASCAR's racing season in 2020.

After that command was given, he and then-first lady Melania Trump led the field of drivers for the event's opening pace lap in the presidential limo -- a memorable appearance that was preceded earlier in the day with a flyover of the track by Air Force One, according to a 2020 Newsweek report.

That Newsweek article highlighted how a pro-Trump political action committee, Patriots for America, had paid $350,000 to sponsor for nine races the No. 32 car driven by Cory LaJoie with advertisements for the then-president's 2020 re-election campaign.

Nor was that the first time that Trump's name appeared on a race car, as USA Today reported in 2016 that the Trump campaign sponsored the car driven by Reed Sorenson at the Texas race right before the election, which followed endorsements of Trump's candidacy by NASCAR CEO Brian France along with several other current and former drivers and team owners.