McLaren launched its new orange-colored MCL32 on February 24.
The British team, powered by Honda engines, was sixth in last year's constructors' standings.
"This year, we have high hopes that McLaren can come back to where it belongs," Fernando Alonso said during the car's unveiling at McLaren's Technology Center in Woking, England.
McLaren team boss Eric Boullier hopes the 20-time world champion -- which last won a title in 2008 -- is "about to turn the corner." The Frenchman added: "The chassis is incredibly well realized, the power unit has been significantly developed and we have a hugely exciting driver pairing that's already blending really well."
Two-time world champion Alonso will be partnered at McLaren by Belgian rookie Stoffel Vandoorne, who has replaced veteran Jenson Button.
Lewis Hamilton and Valtteri Bottas pose with the Mercedes W08 -- the car the dominant German team hopes will fuel further success in Formula One.
Mercedes launched its new car at the UK's Silverstone circuit. Both Bottas and Hamilton (pictured) took the W08 for a spin on Thursday.
Mercedes will be looking to win its fourth successive F1 constructors' championship in 2017.
Hamilton is joined by Bottas -- the Finn replaces reigning world champion Nico Rosberg, who retired a few days after clinching the 2016 title at the season-ending Abu Dhabi Grand Prix.
An overhead shot of former Williams driver Bottas in the cockpit of the new car at Silverstone.
Red Bull is expected to be one of Mercedes' closest rivals this season. Here Daniel Ricciardo drives the new RB13 at winter testing.
Ricciardo finished third overall in last season's driver standings behind Rosberg and Hamilton, with the Australian winning in Malaysia and notching seven other podium placings.
Apart from the Mercedes duo and Ricciardo, Max Verstappen was the only other driver to win a race last season, following his promotion to a Red Bull seat from Toro Rosso. The Dutch 19-year-old is expected to be a title contender this year.
Ferrari unveiled its new SF70-H car on Friday February 24, at its Maranello headquarters in Italy.
It is the 63rd single-seater designed and built by Ferrari since the F1 world championship began, and team bosses will hope for an improvement on last year's third-place finish.
Ferrari's driver lineup will again comprise former world champions Sebastian Vettel and Kimi Raikkonen -- the Finn being the Prancing Horse's last title winner in 2007.
The American Haas F1 team launched its new car on the opening day of preseason testing in Barcelona on February 27. French Romain Grosjean is pictured with new Danish teammate Kevin Magnussen (left).
Felipe Massa, who came out of a brief retirement after Bottas joined Mercedes, drives Williams' new FW40 on day one of winter testing at the Circuit de Catalunya in Montmelo, Spain.
Red Bull's junior team Toro Rosso launched its new car the day before the start of winter testing. Spain's Carlos Sainz drives the STR12 at Circuit de Catalunya.
Sauber was the first team to reveal its new-look car ahead of the 2017 world championship.
New design regulations set out by motorsport's governing body, the FIA, means the 2017 cars will have fatter tires and wider wings at both the front and rear.
Swiss-based Sauber is celebrating its 25th year in F1 -- as can be seen in the gold lettering on its new blue and white livery.
Sauber will be looking to improve on a disappointing 2016 campaign, where it finished in second from bottom in the constructors' championship. The team has recruited Pascal Wehrlein to partner Marcus Ericsson for 2017.
In 2016, Felipe Nasr scored the team's only two points with ninth place at the penultimate race in his native Brazil.
Renault was the second team to launch its 2017 car, on February 21.
The RS17 is the first to be completely designed by the French team since it returned as a works squad, having taken over Lotus last year. "It's a beautiful car," Renault Sport Racing president Jerome Stoll said. "We want to take a definite, tangible step forward in performance and results. Fifth position in the constructors' championship is our goal."
Renault was ninth out of 11 teams last year, but technical chief Bob Bell is predicting performance gains of 5% in 2017.
Germany's Nico Hulkenberg has joined from Force India, while British driver Jolyon Palmer has retained Renault's other race seat. Russia's Sergey Sirotkin is promoted to reserve driver, while four-time world champion Alain Prost will be a special advisor to the team.
Danish driver Kevin Magnussen, who earned seven of Renault's eight points in 2016, will race for the American Haas F1 team this season.
Sahara Force India F1 launched its VJM10 car for the 2017 season on Wednesday February 22.
The launch took place at the team's Silverstone headquarters.
Force India has retained Mexico's Sergio Perez (left) for the 2017 season but Esteban Ocon is a new face. The 20-year-old spent the second half of 2016 at the now defunct Manor Racing team. The Frenchman replaced Renault-bound Hulkenberg.
A close-up of one of the wider front tires that the 2017 cars will be sporting this season.
"I think the 2017 cars are gonna be much more challenging," Ocon (right) told CNN. "I've been spending a lot of time in the gym -- a lot ... two months now ... I will be ready physically for sure but it's been hard!"