Airbus SE announced the biggest commercial-plane transaction in its history, securing an order for single-aisle aircraft valued at nearly $50 billion at the Dubai Air Show, outdoing Boeing Co.\u2019s own $20 billion mega-deal. Wednesday\u2019s pact for 430 A320neo planes with U.S. investor Indigo Partners marked a turnaround for Airbus at the Gulf expo, where it had been trailing its rival. It\u2019s also a crowning achievement for sales chief John Leahy, who is set to retire after a career in which he has struck deals for more than 16,000 jets and lifted the European planemaker into a duopoly position with Boeing. For Indigo Partners, led by Bill Franke, the Airbus accord provides upgraded narrow-body aircraft to boost the fleets of low-cost carriers from Denver to Budapest. The planes will go to four companies in Indigo\u2019s investment portfolio: Frontier Airlines, Mexico\u2019s Volaris, East European operator Wizz Air Holdings Plc and Chile\u2019s JetSmart, which began operating this year. The deal features 273 A320neo jets together with 157 of the larger A321neo variant and is worth $49.5 billion before customary discounts, Airbus said. Leahy, 67, called the transaction \u201cremarkable,\u201d while Franke, 80, who co-founded Indigo in 2002, said it underscores his confidence in the A320 and the bargain fares, no-frills travel model he helped develop. Airbus shares rose as much as 4 percent and were trading 2.9 percent higher at 85.93 euros as of 11:13 a.m. in Paris, taking the gain this year to 37 percent. Boeing Retort Boeing recovered some ground with the sale of 175 737 Max planes, the A320\u2019s main competitor, to FlyDubai, a deal big enough to have dominated most air shows. While that order will come as an irritation for Airbus, with the airline having been expected to split it between the two manufacturers, the Toulouse, France-based company wasn\u2019t done at the Dubai event. It went on to announce EgyptAir Airlines Co. as the operator of 15 A320neos previously ordered by leasing firm AerCap Holdings NV. The Indigo deal more than doubles Airbus\u2019s previous order book for the year, which stood at about 290 aircraft as of Oct. 31, pushes the planemaker\u2019s backlog above 7,000 jets and reverses expectations that orders will trail deliveries in 2017. The haul will also help Airbus catch up to Boeing in the order tally this year, with the European planemaker having chalked up 343 contracts at the end of last month, compared with 690 for its Chicago-based rival as of Nov. 7. The order also trumps a 2015 deal for 250 single-aisle jets worth $27 billion by Indian budget carrier IndiGo. The two companies aren\u2019t related. The massive A320 win takes the sting out of a possible defeat on the A380 superjumbo, which has so far failed to clinch a follow-up deal with local carrier Emirates at the Dubai show. The companies have been in talks on a deal for about 36 additional double-deckers valued at $15.7 billion, people familiar with the negotiations have said. The A380 has become all but a fringe product for Airbus, with a total order book of 317 - more than 100 short of the A320s that Indigo plans to buy. The breakdown of the Indigo order is as follows: Wizz - 146 planes (72 A320neo, 74 A321neo) Frontier - 134 planes (100 A320neo, 34 A321neo) Volaris - 80 planes (46 A320neo, 34 A321neo) JetSmart - 70 planes (56 A320neo, 14 A321neo) Boeing\u2019s 737 deal from FlyDubai includes more than 50 of the largest Max 10s, with the balance to be made up of Max 8s and 9s, according to a statement. The carrier, which is due to integrate more closely with Emirates over coming months, also has options on 50 more aircraft. Emirates itself snubbed Airbus on the first day of the show with a surprise $15 billion order for Boeing 787 wide-body jets, after also looking at the European company\u2019s A350. The Indigo purchase provides a boost to Airbus Chief Executive Officer Tom Enders, who has found himself on the defensive amid an investigation into bribery allegations at the company. Enders has warned employees that the probe is likely to be a drawn-out process that could result in \u201cserious consequences\u201d and \u201csignificant penalties.\u201d A German who has run Airbus for five years, Enders orchestrated another coup last month when he struck a deal with Bombardier Inc. to take a majority stake in the Canadian company\u2019s C Series jet program. That will give Airbus access to advanced technology while throwing Bombardier a lifeline for its slow-selling aircraft. Fly-by-Wire Pioneer The A320 is Airbus\u2019s best-selling product and the aircraft that put the company on the map when it was introduced in the late 1980s with cutting-edge technology such as fly-by-wire controls and a side-stick to steer the plane rather than Boeing\u2019s central yoke. Airbus was first to pioneer the new-engine variant of its existing single-body model. The A320neo first flew in 2014 and has been delivered to customers around the world. Boeing\u2019s response, the 737 Max, only entered commercial service this year. Narrow-body aircraft, which typically seat six abreast in economy class, are the workhorses of the global airline fleet. Burgeoning demand for air travel will push jetliner sales to more than 34,000 worldwide in the next 20 years, according to Airbus\u2019s 2017 global market forecast. Almost three-quarters of that will be single-aisle models, the company said. While a huge commercial hit, the A320neo hasn\u2019t been without technical faults. Output is being disrupted by manufacturing delays at Pratt & Whitney, a unit of United Technologies Corp., which supplies the plane\u2019s geared turbofan engine. The A320neo is also powered by engines made by CFM International, a venture between General Electric Co. and Safran SA. Airbus makes the A320 family at different sites around the world, including its main factory in Toulouse, France, as well as in Hamburg, Germany. The company also builds the plane at an assembly line in China, and has recently pushed into the U.S. with a plant in Mobile, Alabama.