McLaren admits it is "not completely happy" with its newly-launched Formula 1 car for 2023.

The latest teams to launch their respective cars for the new season are McLaren and Aston Martin - with Alpine carrying out a low-profile 'shakedown' at Silverstone.

Red Bull boss Christian Horner is expecting the midfield teams to improve this year.

"Alpine was making good progress in the second half of last year," he said. "And we keep hearing big things about Aston Martin's expectations.

"You just don't know what the pecking order will be," Horner told Auto Motor und Sport.

Aston Martin plans to move into a brand new factory at Silverstone this year, with owner Lawrence Stroll determined to join the big teams at the front.

"Over time, we want to become real leaders of the championship," said the billionaire on Monday.

New recruit Fernando Alonso also has big ambitions.

"We will not be happy with fourth, third, second," said the 41-year-old Spaniard, who has moved from Alpine over the winter.

"Maybe we cannot win immediately, but it's something we need to make sure - that this car is the baseline for future years."

Former F1 driver Ralf Schumacher, however, scoffed at Alonso's claim that team owner Stroll's son Lance has the potential to win a drivers' title.

"And Formula 1 cars can fly," the German joked. "Or is it already the first of April?"

Aston Martin deputy technical boss Eric Blandin, though, insists the 2023 car has some "clever innovations" taking advantage of certain rule loopholes.

McLaren, on the other hand, is keeping expectations low - having finished behind Alpine for fifth in the constructors' standings in 2022.

"There are some other areas of the car that will be improved by early season developments," new team boss Andrea Stella, who replaces new Sauber CEO Andreas Seidl, said.

"So we're happy, but not completely happy with the car as it is at launch."

Lando Norris, kicking off his fifth consecutive season in Formula 1 with McLaren this season, admits he will need to remain "patient" for success.

"I am probably not the most patient guy in the world, but it is something you need to learn to have in F1," said the 23-year-old, whose new teammate is rookie Oscar Piastri - replacing the experienced Daniel Ricciardo.

"You can't expect us to be level with the Red Bull and Ferrari and Mercedes this year," insisted Norris. "There is still a way to go for that."

There are rumours McLaren supremo Zak Brown recently met with Red Bull Powertrains to assess engine options for 2026, while 21-year-old youngster Piastri will kick off the new year trying to put the Alpine contract saga behind him.

"Like many other things, I think time is the best healer," said the Australian.