A rising economy and more than a dozen new destinations will make it easier for passengers looking to fly out of Minneapolis-St. Paul International Airport this year.

Fourteen domestic and international routes, including two from Minnesota's own Sun Country Airlines, are being added. Airport officials listed economic reasons for the sudden increase in routes.

Low operating costs, high demand for travel and a strong local economy all play a role in airline decisions to add routes, said Melissa Scovronski, spokesperson for the Metropolitan Airports Commission.

As Minnesota's economy continues to rebound — the unemployment rate ticked down again in December to 3.5 percent — MSP tries to keep costs down to attract affordable airlines, thereby making it cheaper for Minnesotans to travel and boosting demand.

"We get Spirit and Frontier, who are both considered ultra-low-fare airlines, so more people are able to fly that weren't able to fly before," she said.

Scovronski said MSP employs fewer people than comparable airports in other parts of the country. In 2014, for example, the airport budgeted to employ 591 people, she said.

That helps keep airport fees low for airlines. An airline's cost of operating at MSP was estimated to be $6.84 per passenger in 2014, which is in the lower third of costs for large hub airports.

Nationally, last year brought higher profits for airlines. Southwest Airlines made a record $536 million in profits in the fourth quarter of last year, and is adding two daily flights between Baltimore and MSP.

Scovronski said the higher profits, as well as the high number of seats filled on many flights — 85 percent and up — has convinced airlines to start new routes across the country.

Trends toward larger, more profitable planes and lower fuel prices over the last few decades also served to increase profits, she said, adding that airlines also are quick to eliminate unprofitable routes.

Delta Air Lines, which also turned in a strong economic performance last year, plans to introduce flights from MSP to Rome as well as to Reykjavik, Iceland.

Ben Farniok is a University of Minnesota student on assignment for the Star Tribune.