Upgrade to an Allegiant Air "Giant Seat"

Allegiant Air's Giant Seats are a roomier 25 inches in width, up from the standard 17.5 inches.

(Photo Allegiant Air)

Allegiant Air passengers flying to Hawaii can now say "aloha" to "Giant Seats." The airline has supersized some economy rows on Boeing 757 airplanes for long-haul flights to Honolulu, Maui, and some western U.S. cities.

Although they've only been offered for a couple of weeks, "generally we're seeing people purchase them, so there is a demand for them," Allegiant Air spokesperson Jessica Wheeler told Yahoo.

The airline made the change to comply with FAA rules that require wider seats for crew members who need to rest during longer flights. The seats are a roomier 25-inch width, up from 17.5 inches.

The airline decided that in addition to those required seats, paying customers might also enjoy (and pay for) a bigger seat on longer flights. Passengers can now reserve them on some flights to Hawaii and Las Vegas. The "Giant Seats" are available for a fee on all six of the airline's 757s, which fly the longer distances.

For those who want to stretch out, the seating arrangements also include a "Legroom +" option, which gives travelers an extra six inches of space, with up to 34 inches of legroom between rows.

In order to make these changes, the number of available seats on the retrofitted planes has gone down from 223 to 215.

Allegiant isn't the only airline making some updates to its economy seating. Many airlines now offer customers the option of premium features and perks, such as extra legroom, priority seating, priority boarding, and free checked luggage.

Virgin America offers "Main Cabin Select," with "six extra inches of legroom," according to its website.

US Airways has "Choice Seats," which are mostly aisle and window seats, some in exit rows, at the front of the plane. Although there's no difference in seat size, travelers are among "the first to board (with Zone 2) and among the first to leave."

United offers "Economy Plus," which gives travelers extra legroom.

JetBlue promotes its "Even More Space" option, with seats that promise "up to 38 inches of legroom."

Travelers who choose Delta can opt for "Economy Comfort," with up to four more inches of legroom and priority boarding.

American has "Main Cabin Extra" seats with up to six inches of extra legroom and priority boarding.

Even Southwest will offer slightly wider seats, from 17.2 to 17.8 inches, on its 737 Max Jets starting in 2017, according to Bloomberg News.

While your seat will be bigger, your wallet will be lighter. The cost of an Allegiant Air "Giant Seat" upgrade will run about $40 to $50 a flight, according to the Chicago Tribune. These days, there's no such thing as free elbow room.

(Claudine Zap - Compass)