It’s been an eventful week for three U.S. airlines, which have debuted new looks for their airplanes. Last week, Southwest Airlines revealed the all-new Southwest Heart, which includes a rebranding campaign as well as a new livery design. Frontier Airlines announced a new logo that acts as a tribute to its past, and the plane design still includes the animal decals. Yesterday, Spirit Airlines revealed its new look—a bright yellow plane.

Spirit Airlines

Spirit Airlines, which prides itself as the “ultra-low cost airline of the Americas” has a new look that is designed to get attention—even at 35,000 feet. The plane is bright yellow, and the letters spelling out Spirit are a bit rough around the edges.

Previously, the fuselages of the planes were white, and the tails were blue with a design in red, green, yellow, and blue.

This new look comes as the airline is promoting its latest concept—the Bare Fare. Instead of including the cost of a bag or drink in the price of a regular ticket, the cost of airfare only includes the plane ticket.

Still not sure how it works? Check out the video below:

This is Spirit from Spirit Airlines on Vimeo.

Frontier Airlines

Last week, Frontier Airlines revealed its new look, which is not a big departure from its previous livery design.

The animals stay, but the F in Frontier has unique lettering, which is a nod to the airline’s history. Frontier Airlines first began in 1950, and stopped service in 1986. During that time, a similar F was located on the tails of Frontier planes in white and red.

Shortly after revealing its new look, Frontier began service from Chicago’s O’Hare airport, with service to Washington Dulles Airport. Starting next month, the airline plans to add six more destinations from O’Hare, and is decreasing its service out of Chicago’s Midway Airport.

Southwest Airlines

Southwest Airlines was the first to announce its new look, which comes with an entire re-branding effort that aims to elevate the airline’s presence in the market. The changes include a new livery design, a new heart logo, a new, user-friendly approach to online and airport experiences, redesigned in-flight material, and a revamped mobile app.

The airline has been in business for the past 20 years, but some recent events have sparked this new change. Southwest acquired AirTran Airways in 2011, and the integration of the two airlines is nearly complete. The Wright Amendment will soon be repealed, which will allow the airline to add more international flights.

Southwest first began flying internationally in July of this year to Mexico and the Caribbean, and the airline recently announced it will be adding flights to Costa Rica. The airline has also stated that starting November 2, it will begin travel to Mexico City and Punta Cana in the Dominican Republic, pending government approval.

The biggest change is the airline’s look—the planes are now bright blue, the logo is in large white lettering, and the tail has lines in yellow, red, and blue. There is a large heart on the belly of the plane, and there’s even a hashtag to accompany the new look—#SouthwestHeart.

For more ways airlines are shaking up travel, check out:

• Themed Planes: Theme Parties at 30,000 Feet
• Need A Laugh? The 5 Most Entertaining Airline Safety Videos

By Stephanie Ervin with Neil Thigpen for PeterGreenberg.com