Frontier Airlines on Wednesday announced huge changes to its fee structure, including charges for beverages and overhead bin space for some customers.

The changes are another step in the airline's effort at steering more passengers to directly book air travel on its website.

The Denver-based carrier will begin charging for carry-on bags by the summer for customers who buy the "Basic" fare — which is the cheapest bracket only offered on third-party sites.

Meanwhile, every ticket purchased on FlyFrontier. com will include a free carry-on, including the Economy fare — which is the cheapest fare available on the airline's website.

A carry-on bag is considered larger than a "personal item." The airline allows every passenger — no matter what price bracket or site he or she used — a free personal item if it fits under the seat.

"Frontier's most loyal customers have made it very clear that finding overhead bin space for carry-on bags has become unacceptably difficult," said Frontier in a news release. "Frontier guarantees that customers will get the best value at FlyFrontier.com with our Best Fare Guarantee."

Customers who do choose to purchase through outside websites can pay between $25 and $100 for a carry-on bag. The cheaper rates will apply to customers who check-in for their flight on its website.

Frontier, which still tries to cater more to the business traveler than other low-cost carriers, hopes these changes will benefit its frequent fliers and status members.

"With this change, we are ensuring that our most loyal customers - Ascent and Summit level members of EarlyReturns, those who book Economy, Classic and Classic Plus tickets, including all customers who book through FlyFrontier.com, will have more space onboard the aircraft for their carry-on bags," said David Siegel, Frontier's chief executive officer. "As we unbundle our product further, we ensure those customers who want the absolute lowest fares can always find them at FlyFrontier.com."

"Unbundling" is an industry-wide trend that allows passengers the choice of paying only for those services and amenities that he or she chooses.

Most airline analysts agree that unbundling is the way of the future for airlines as they struggle to turn a profit.

"(Airline) fares are virtually unchanged from this time last year, so I think fees will continue to be a part of everyone's approach," said Robert Polk, chief executive of Polk Corporate Travel Management in Denver. "It does require a lot more thought than it used to. You have to weigh a lot more things than you ever had to prior."

There are only three price brackets on Frontier's website — Economy, Classic and Classic Plus. All customers who are status members or purchase Classic or Classic Plus tickets will be able to fly both their checked luggage and their carry-ons for free.

Those who purchase Basic or Economy tickets can fly a checked bag for $20 if they buy it on the website. But, if these same ticketholders decide to wait until they reach the airport, the cost will bump up to $25 for the first bag.

Also, beginning in July, the carrier will begin charging customers with Economy or Basic fares about $2 for onboard beverages, but they will still be free for Ascent and Summit level members.

And, finally, Frontier will change its frequent flier program's accrual rate on July 1 for passengers who purchase a Basic fare ticket. Instead of accruing 50 percent of the miles flown, those passengers will only accrue 25 percent. Economy, Classic and Classic Plus ticket-holders will continue to receive 100, 125 and 150 percent, respectively, of the miles flown.

A Frontier airplane taxis to head out of Denver International Airport Thursday morning.
A Frontier airplane taxis to head out of Denver International Airport Thursday morning. (Andy Cross / Denver Post)

The changes apply for any tickets purchased after Wednesday's announcement for travel beginning July 1.

Kristen Leigh Painter: 303-954-1638, kpainter@denverpost.com or twitter.com/kristenpainter