News broke yesterday that AirAsia's CEO Tony Fernandes held talks with Airbus COO John Leahy and CEO Tom Enders about a mass purchase of the A320NEO. According to Fernandes the order would be similar in size to the existing order for 175 A320, so expect something like a firm order for 100 and a further 50 options or so to be announced soon. Maybe together with the also "pre-announced" order for more A330's, maybe firmed during the Paris Air Show in June.
If you look at AirAsia and the other two carriers which came forward to order or to sign an LoI for the NEO, it becomes clear who are the prime targets for Airbus when the A320NEO was launched: the fast-growing LCC's in Asia (IndiGo, AirAsia, Tiger) and elsewhere (Virgin America in this case). A few years back the prime targets would have been on different continents - this is a clear sign of how the world has changed in the last decade.
Why are these large LCC's attractive (potential) customers)? They already have (or will have in 2016) large fleets - adding another subtype (in case of the NEO it's "just" another engine) in an equal large scale does not produce a lot of headaches. And by being one of the launch customers for one of the NEO engines, they can bet on getting good deals not only regarding the purchase price of the engines but also for aftermarket packages. Remember IndiGo was the launch customer for the V2500Select.
Even Ryanair, at least in public, talks about adding another type to their B737-800 fleet, altough that might be just chatter get better pricing from Boeing. Southwest though, already having different types of the B737 in their fleet and adding the B717 with the purchase (merger) of airtran can be expected to have a closer look to diversifying the fleet more, but this would, if at all, point more in the direction of the CS300 (or a CS500) to replace the B737-300 and later -700.
So expect to see more big orders for the A320NEO from LCC's - but not only from LCC's...