MIAMI — Gurgaon, India-based IndiGo today signed a major Memorandum of Understanding (MoU) for 250 firm Airbus A320neos, the manufacturer’s single-largest aircraft order. IndiGo is a domestic and international low-cost carrier founded by Rahul Bhatia of conglomerate InterGlobe Enterprises and Rakesh Gangwal, the former chairman and CEO of US Airways from 1998 to 2001.

The carrier, based at Delhi Indira Gandhi International Airport, currently has 83 A320-200s. It has existing orders for 280 Airbus aircraft — 100 A320ceos and 180 A320neos. IndiGo serves 31 cities in India, along with flights to Bangkok, Dubai, Kathmandu, Muscat and Singapore for a total of 540 daily flights. The airline’s business model resembles that of Southwest Airlines — one common fleet type, a focus on keeping costs low and an obsession with on-time operations.

Since its beginnings in 2006, IndiGo has been the fastest-growing carrier in India. Among domestic airline in the second quarter, IndiGo’s market share was 31.6 percent, the best among its competitors, according to India’s Directorate General of Civil Aviation. Air India was 18.5 percent while SpiceJet was 18.3 percent.

The aircraft covered under the MoU includes what Airbus calls the “new engine option,” along with large sharklet wing-tip devices, which offer carriers 15 percent in fuel savings now and up to 20 percent by 2020. Airbus currently has orders for 49 A319neos, 2,494 A320neos and 729 A321neos from carriers including Swiss, Eurowings, JetBlue, China Eastern airlines and Air New Zealand.