Question: Which low-cost airline is headquartered in Sydney?

Context paragraphs:
Blue Air: Blue Air is an airline headquartered in Bucharest, with its main hubs at Henri Coandă International Airport and Turin Airport.  Since 2016, it has become the largest Romanian airline by scheduled passengers flown.  In 2016, Blue Air carried 3.6 million passengers, a significant increase over the 2 million passengers flown the previous year.  As of May 2017, Blue Air flies to 70 destinations.  Despite operating as a low-cost airline, Blue Air started introducing free sandwiches and drinks on-board shorter flights, and a full hot meal, snacks, hot/cold and alcoholic beverages on longer flights.  This is considered unheard of in the low-cost sector, particularly as traditionally 'full service' carriers such as British Airways controversially removed free meals, snacks and drinks in 2017, and is considered key to Blue Air's continued success.

Philippines AirAsia: Philippines AirAsia, Inc. (formerly Zest Airways, Inc. dba AirAsia Zest), is a low-cost airline based at Ninoy Aquino International Airport in Metro Manila in the Philippines.  The airline is the Philippine affiliate of AirAsia, a low-cost airline based in Malaysia.  The airline started as a joint venture between three Filipino investors and AirAsia Investments Ltd., a subsidiary of AirAsia Berhad.

U-Land Airlines: U-Land Airlines (Chinese: 瑞聯航空; pinyin: Ruìlián hángkōng) was a Taiwanese low-cost airline.  The company was the first low-cost airline company in Asia, which operates domestic and short range international routes.  Bankrupted in 2001, it was affiliated to U-Land Building Co., Ltd before it ceases, and is the first airline company bankrupted in Taiwan.

Jetstar Airways: Jetstar Airways Pty Ltd, trading as Jetstar, is an Australian low-cost airline (self-described as "value based") headquartered in Melbourne.  It is a wholly owned subsidiary of Qantas, created in response to the threat posed by low-cost airline Virgin Blue.  Jetstar is part of Qantas' two brand strategy of having Qantas Airways for the premium full-service market and Jetstar for the low-cost market.  Jetstar carries 8.5% of all passengers travelling in and out of Australia.

Low-cost carrier: A low-cost carrier or low-cost airline (also known as "no-frills", "discount" or "budget" carrier or airline, or "LCC") is an airline that generally has lower fares and fewer comforts.  To make up for revenue lost in decreased ticket prices, the airline may charge for extras such as food, priority boarding, seat allocating, and baggage.  As of July 2014, the world's largest low-cost carrier is Southwest Airlines, which operates in the United States and some surrounding areas.

Sydney Airport: Sydney (Kingsford Smith) Airport (colloquially Mascot Airport, Kingsford Smith Airport, or Sydney Airport; IATA: SYD, ICAO: YSSY ; ) is an international airport in Sydney, Australia located 8 km (5 mi) south of Sydney city centre, in the suburb of Mascot.  It is the primary airport serving Sydney, and is a primary hub for Qantas, as well as a secondary hub for Virgin Australia and Jetstar Airways.  Situated next to Botany Bay, the airport has three runways, colloquially known as the east–west, north–south and third runways.

Tigerair Mandala: Tigerair Mandala ("formerly Mandala Airlines") was a low-cost airline headquartered in Jakarta, Indonesia and is an associate company of the Singapore-based Tigerair Group.  The former full service airline repositioned itself as a budget airline/low-cost carrier (LCC) following a year-long grounding in 2011 caused by debt woes.  Mandala resumed operations in April 2012 following an injection of fresh capital by Indonesian conglomerate Saratoga Investment Corp which took over 51% of the airline, with partner Tigerair taking up 33.3% and the rest by creditors.

IndiGo: IndiGo is a low-cost airline headquartered at Gurgaon, Haryana, India.  It is the largest airline in India by passengers carried and fleet size, with a 38.7% market share as of July 2017.  It is also the largest individual Asian low-cost carrier in terms of jet fleet size and passengers carried, and the eighth largest carrier in Asia with over 41 million passengers carried in 2016.  The airline operates to 46 destinations both domestic and international.  It has its primary hub at Indira Gandhi International Airport, Delhi.

List of low-cost airlines: The following is a list of low-cost carriers organized by home country.  A low-cost carrier or low-cost airline (also known as a no-frills, discount or budget carrier or airline) is an airline that offers generally low fares in exchange for eliminating many traditional passenger services.  Regional airlines, which may compete with low-cost airlines on some routes, are listed at List of regional airlines.

Lion Air: PT Lion Mentari Airlines, operating as Lion Air, is an Indonesian low-cost airline.  Based in Jakarta, Indonesia, Lion Air is the country's largest privately run airline, the second largest low-cost airline in Southeast Asia after AirAsia and the second largest airline of Indonesia, flying to more than 79 destinations in Indonesia, Singapore, Malaysia and Saudi Arabia, as well as charter routes to China, Hong Kong and Macau.

Supporting paragraphs: Sydney Airport Jetstar Airways
Answer: Jetstar Airways