Frontier Airlines raising baggage fees

• The increases range from %245 to %2410 per bag

Frontier Airlines, which has expanded rapidly in Phoenix and other cities, is raising its baggage fees in May.

The increases, which take effect for travel on or after May 1, range from $5 to $10 per checked bag, according to the baggage fee chart on the airline's website. The biggest increase is for bags checked last-minute at the gate. The price will go from $50 to $60.

Other baggage fees are going up by $5. Frontier, like fellow discounters Spirit Airlines and Allegiant Air, has a dizzying list of baggage fees, with prices based on where you buy your ticket and when you pay for the bags.

The baggage fee during online check in is going from $20 to $25 and the fee at the airport is going from $25 to $30, both for one checked bag. A second checked bag at the airport is going from $30 to $35.

Travelers who buy their tickets on Frontier's website and pay for their bags at the time of booking or anytime before getting to the airport do not face higher fees. Their first checked bag will remain $20, the second bag $30, each lower than the industry standard of $25 for the first bag and $35 for the second bag. At the airport, though, their baggage fee will go from $25 to $30 for the first bag and $30 to $35 for the second checked bag.

Travelers who book Frontier tickets through the airline's reservations center will pay $30 for bags if they pay for them in advance, up from $25.

Frontier, which last year joined Spirit and Allegiant in charging for carry-on bags that don't fit underneath the seat, is not raising its carry-on bag fees. They range from $30 to $40, depending on the time of purchase.

Southwest Airlines is the only major carrier not charging for the first two checked bags.

Frontier is owned by Phoenix-based Indigo Partners, an investment firm headed by former America West Airlines Chairman and CEO Bill Franke. The firm previously was the majority investor in Spirit Airlines.