Brave New Fees

AirAsia offers an inflight chat service though its Wi-Fi network for less than $3 (U.S.) to support apps such as WhatsApp and WeChat.

Spirit Airlines gets subscription revenue from its $9 Fare Club, whose members get access to special fares and discounts on bag fees. However, the annual fee starts at $59.95.

EasyJet sells an annual subscription called easyJet Plus, which includes assigned seating, fast-track security, speedy boarding and an additional carry-on bag for an annual price of £170 ($340).

Allegiant offers everything for a vacation, from rental cars and hotel rooms to attractions and show tickets. The airline earns a 30-per-cent gross margin on the sale of services provided by third parties.

Tigerair offers a service for passengers with connections in Singapore that exceed eight hours that includes a city-centre shuttle and sightseeing tour for about $18 (U.S.).