Top ten low-cost airlines by revenue: Southwest leads globally

Frontier Airlines from the United States stands eighth with $3.66 billion annually, serving 103 destinations using Airbus aircraft. Frontier is recognized for its animal-themed aircraft tails.

AirAsia of Malaysia ranks seventh, earning $4.37 billion per year while operating a red-painted fleet across Asia-Pacific regions with a focus on Airbus planes.

Spirit Airlines, another U.S.-based carrier known for its yellow livery, ranks sixth at $5.06 billion in revenue, operating an extensive network of low-cost routes.

Hungary's Wizz Air comes fifth with $5.57 billion annually, featuring a purple two-tone livery and operating numerous European routes using Airbus jets.

Jet2 from the UK takes fourth place at $6.23 billion, flying both Airbus and Boeing models primarily to leisure destinations.

The UK's easyJet ranks third globally among budget airlines with $9.96 billion in annual revenues, operating an all-Airbus fleet across Europe from various bases.

Ireland's Ryanair stands second among low-cost carriers worldwide at $14.96 billion yearly revenue, utilizing mainly Boeing 737s for its vast network of routes across Europe and beyond.

Topping the list is Southwest Airlines from the United States with an impressive $27.37 billion in annual revenue—the highest among low-cost carriers globally—using a substantial fleet of Boeing 737s to serve primarily domestic routes within the U.S.