Aer Lingus – Ireland's national flag carrier took the bold step of repositioning itself as a low-cost airline after the financial crisis of 2008 left it struggling with heavy losses and facing drastic staff cuts.
WestJet – One of the oldest airlines on this list, Canada's WestJet was launched in 1996. Based in Calgary, it offers destinations, some via code share, across Canada, America, the Caribbean, Ireland and the UK.
HK Express – Founded in 2004, HKExpress transformed itself into a low-cost carrier in 2013 in an effort to reverse its troubled fortunes. AirlineRatings.com says all the budget carriers on its list have passed stringent International Air Transport Association operational safety audits, unlike many of their rivals.
JetBlue – Now in its 16th year, JetBlue originally sold itself as being a cut above other no-frills airlines, by claiming to offer better in-flight entertainment perks. It operates out of New York's JFK airport and has a fleet of more than 210 aircraft.
Jetstar – A budget offshoot of Aussie carrier Qantas, Jetstar has hubs in most major Australian cities. Its 70-strong fleet connects 35 destinations. Beyond Australia, it has also served connections to New Zealand, Fiji and China.
TUIfly – Hanover, Germany-based airline TUIfly was formed in 2007 to serve the low-cost sector and package vacation operators. It offers connections across Germany, southern Europe, northern Africa and the Middle East.
Virgin America – Serving 24 destinations with a fleet of 58 aircraft, Virgin America is part-owned by British entrepreneur Richard Branson's Virgin Group. It was founded in 2007 and is headquartered out of California.
Volaris – Now Mexico's second largest airline, Volaris was founded in 2005. The carrier mostly serves destinations in Mexico and America, including flights to Los Angeles, Dallas and Chicago.