Small airlines use a collection of software between their business, if they do their own maintenance they use a tool like AMOS (http://www.swiss-as.com/main.do) which is produced by a subsidiary of Lufthansa, then another tool like sabre (http://www.sabreairlinesolutions.com/home/software_solutions... ) to manage crew, flights planning etc. Bigger airlines will probably use SAP.

The hardware is going cloud based/vm but due to a ton of legacy and regulation concerns (i.e. data protection, rules regarding data access in the event of accidents etc) it's very slow going and most companies will still host their own servers, with maybe a company-wide shared oracle/db instance.

The market is strangely competitive, though it has become quite stale in my opinion. RAMCO (http://www.ramco.com/aviation-suite/campaign/aviation/) are the closest thing to a "disruptive" force, but their software is widely regarded as flashy with little meat to it (and a lot of glitches).

Source: developer for one of the MRO software providers (not listed here)

Yeah correct - flight planning, crew is managed by Sabre FPM and Crew Manager (afaik). ACARS are managed through FPM , HERMES and some strange interface for the old mainframes (the rest of the comm is going through this). The rest is mostly SAAS, but in the RDP sense. I can assure you, its definitely not "Cloud", but Remote Desktop Computing. SAS also has multiple small airlines (local) attached to it, some of them are using their own stuff, but most of it is central.

This is by far one of the most stale industries as yarper mentioned. Really long sales cycles heavily relying on connections and also large implementation/customization fees are part of it. Esp. in flight planning - where 0.1% fuel savings are important, things haven't moved anywhere.

More than 100 airlines worldwide are using Amadeus (amadeus.com) today. There are different components to it such as Amadeus altea inventory (for managing their flight inventory, prices etc), altea reservation and altea DCS (for check-in and boarding). Additionally there are products to manage their websites (such as the e-commerce solution of Amadeus), revenue management systems etc. The main competitors are sabre (as mentioned) but also HP, Accenture, SITA and others are providing solutions in the same field.

It's a pretty mature industry and btw one of the first ones to move to the cloud.