Sun Country Airlines is launching a first-of-its-kind partnership bridging land and air to attract more travelers from cities like Mankato and Duluth.

Starting next week, customers will be able to book trips on Sun Country that begin and end at the Mankato or Duluth airports, executives said Tuesday. But the first leg of the trip — from Mankato to Minneapolis-St. Paul International Airport, or from Duluth to MSP — will be on a 56-seat coach bus operated by a new company called Landline.

Sun Country is Landline’s launch customer and Minnesota will be the first market to test the concept. Los Angeles-based Landline was started by two former employees of Alaska Airlines who noticed rural markets across the U.S. had diminishing access to affordable air travel.

That is largely because of a shift in the types of airplanes airlines use. The Big 3 airlines that have large enough fleets to serve smaller markets are getting rid of small, 50-seat aircraft. The 100-seat airplanes that have replaced them are too big to serve those small markets. Meanwhile, the budget carriers, such as Spirit and Frontier, typically don’t service those small markets.

This, said David Sunde, chief executive and co-founder of Landline, is why he and his business partner, Ben Munson, started the company.

“Small- to midsize cities across the U.S. have not really participated in the rise of the ultra-low-cost carriers,” Sunde said. “When we started the company, our goal was to get those travelers more connected to the national transportation system.”

For travelers in Duluth and Mankato, Landline fares will be included in the price of the Sun Country ticket. Customers book the bus portion of their trip as if it were just another leg of their flight.

Passengers will be checked in to Sun Country’s system, allowing the airline to know they are on their way, as are their bags. This shifts the burden of arriving on time from the passenger to them, Landline executives said.

Landline executives said the company can offer a cheaper ground-transportation option — a price that is baked into the ticket fare — than the current airport shuttle industry because it knows exactly when it needs to arrive at the airport for its customers and can operate fewer, but fuller, loads every time. Those savings, Munson said, are then passed on to the passenger.

Over the summer, the bus company tested its system as a traditional shuttle service in Duluth and Mankato, typically carrying around 10 passengers each way. But, beginning Oct. 24, the bus service will be available on Sun Country’s booking website for flights departing on or after Nov. 4.

“We want to attract more people that are between 90 minutes and five hours’ drive to this airport,” Jude Bricker, Sun Country’s chief executive, said. “We want to give low-fare opportunities to smaller communities. It’s just like buying an airline connecting fare. You start your journey right in your hometown.”

Bricker said it’s a way for Sun Country to expand its geographic reach across Minnesota, Wisconsin and the eastern edge of the Dakotas without competing with Delta Air Lines’ profitable business commuters.

If all goes well, Sun Country and Landline imagine expansion to other Midwest cities, such as Madison, Wis., Fargo, Brainerd, Bemidji, La Crosse, Wis., and Eau Claire, Wis.

“We know where people live who buy our tickets,” Bricker said.

Munson of Landline said the company chose to use the Mankato and Duluth airports because they have nice facilities and ample parking.

Plus, he said, they want the experience to feel as much like the airline experience as possible.

Landline said its main competitors are customers who drive themselves to airports. The company has already hired 44 people in Minnesota, both full- and part-time, to serve as customer-service agents at the airports and onboard attendants to help answer questions and direct customers.

It runs four round trips to Duluth and five round trips to Mankato daily. Landline contracts with Lorenz Bus Service Inc. to perform maintenance and provide bus drivers.

One of the biggest stresses for passengers coming from other cities for MSP departures is budgeting their time, said Brian Davis, Sun Country’s chief marketing officer.

“The value is really that Sun Country takes responsibility for you once you check in to the bus,” Davis said. “We only offer options that will give you enough cushion to get through security on time.”