Michael Andretti has hit back at existing Formula 1 teams who are opposed to the expansion of the grid to eleven teams.

The most visible and arguably qualified entrant currently waiting for Liberty Media and the FIA's decision amid a current tender process is Andretti-Cadillac.

But Mercedes boss Toto Wolff reiterated his opposition last weekend.

"Our position was very clear - buy a team," he said at Silverstone.

When asked if he agrees with that position, Ferrari's Frederic Vasseur added: "Yeah.

"We have a huge boom in Formula 1 now, but you have to keep in mind that a couple of years ago, when the crisis was there, the owners of the teams made a huge effort and the benefit is today," he said.

It is expected that the FIA will update the prospective entrants, including Andretti, about the status of their applications on July 15.

Former F1 driver Michael Andretti, whose racing empire is present in Indycar, Formula E and elsewhere, said the 11th team is the only way he can enter Formula 1.

"We have contacted all the teams, but no one is interested," he told reporters at the Extreme E race in Sardinia, according to France's Auto Hebdo.

"They keep saying 'buy a team', but nobody wants to sell. They are not even interested in a discussion."

And so, the 60-year-old American says he is putting his trust in F1's authorities.

"In the end, the teams are not the ones who will make the decision," Andretti said. "It will be up to F1 and the FIA to decide if they think us coming in is a good thing."

He also hit back at suggestions that General Motors and Cadillac are only being associated with the Andretti bid in order to get it over the line.

"People try to say 'they're just putting their name on it', but it's not like that. They are an integral part of the team," Andretti said.

And so, if there are two Andretti-Cadillac cars on the grid as soon as 2025, the identity of at least one of the drivers is already clear - Colton Herta.

"Colton is part of the project," Andretti confirmed. "He is still so excited to join us, and I would love for him to be involved in this category.

"He's tested the McLaren and did very well. I'd like him to be the first competitive American in F1 for a long time."