It’s official, Frontier Airlines will be the name going forward when Midwest Airlines and Frontier Airlines integrate over the next 12-18 months.

“Although both brands have built strong affinities with air travelers, our customer research concluded that Frontier is the brand best positioned to meet the needs of today’s consumers with its affordable-fares brand promise,” said Ian Arthur, Republic’s vice president of Marketing and Branding in a Republic Airways Holdings press release.

Republic says that they plan to expand service in both Denver and Milwaukee hubs starting with 10 new destinations for Denver and five for Milwaukee in 2010 as well as adding 1,200 jobs in Milwaukee and 4,100 in Denver. The frequent flyer program will be branded Frontier EarlyReturns and will have teams in both Milwaukee and Denver. The call centers in both cities will also stay in place.

Steve Mathwig Director of Loyalty Marketing at Midwest Airlines says, “We started aligning the loyalty programs earlier this year so all the benefits, accruals and awards in the programs would mirror each other.” He points out that the elite status tiers now match after implementing changes earlier this year. The frequent flyer system platform will be managed by TradeOne Marketing, Midwest’s current system provider.

Mathwig reports that the combined membership number stands at around 2.6 million active members–members with activity within 24 months–and that the overlap of members is very small.

The airlines plan to have a combined reservations system in place by November, but the frequent flyer program integration should be complete by early fall. The transition will be automatic with members of each program retaining their current membership number. Members who have accounts in both programs will be contacted regarding which account number to use. The programs will continue to operate independently through the summer months.

Unique to an integration like this is that both loyalty programs partner with Barclays Bank Delaware for their co-branded credit cards so the change to one program will be easy for cardholders–they’ll even be able to keep the same credit card number.

Republic has launched a dedicated Web site at http://www.FrontierMidwest.com where customers can get details about the integration process. Members of both programs will continue to get updates via email and the two airlines’ Web sites until the two sites are combined this fall.

Bottom line: So far, it looks like smooth sailing as these two airlines integrate. The Frontier Airlines animals on the tails of the planes will continue and the first new animal to be introduced will be a badger (Wisconsin’s state animal). For Midwest fans, the chocolate chip cookie is also to be retained, “Cookie lovers can breathe a sigh of relief because the chocolate chip cookie isn’t going anywhere. We are currently working to determine the best way to introduce the cookie on all of our flights …” reads the FAQ.