British Airways and Iberia parent company IAG says a shift towill cut costs and improve collaboration among its 58,000 airline staff.
Along with the subscription-based online Office 365 business suite, the deal announced on Wednesday between Microsoft and the aviation group covers a number of the software giant's cloud-based services.
The agreement includes mail and calendaring product Exchange Online, collaboration tool SharePoint Online, Lync Online instant messaging, and social network service Yammer.
"Office 365 will allow employees to collaborate and achieve their work tasks regardless of the platform, product or device," IAG chief information officer Nigel Underwood said in a statement.
He added that creating a common IT platform for airlines across the group "will be more efficient and reduce our costs".
IAG said the Microsoft deal will allow the organisation to consolidate systems.
"Office 365 and Yammer will enable us to switch off legacy email and related systems, including about 1,000 bespoke applications," an IAG spokeswoman said.
Deployment is already underway, according to IAG, with the planned rollout focusing initially on key areas where multiple systems are currently in place.
The shift to Microsoft Office 365 will entail measures to ensure appropriate security is in place and some changes to IAG's IT infrastructure, which form part of the company's overall strategy to move towards cloud-based services.
Microsoft said the use of social tools was an important part of the airline's strategy for improved internal communication and collaboration.
It added that Yammer offers a secure, private enterprise network for staff to collaborate and share information across business units and locations.
IAG — or International Airlines Group — was created in 2011 from the merger between UK carrier British Airways and Spanish national airline Iberia, and now has a fleet of 420 aircraft flying more than 69 million passengers to 230 destinations annually.
The group, which also includes Vueling Airlines, IAG Cargo and rebranded Air Miles business Avios, describes itself as Europe's third largest airline company and the world's sixth largest by revenue.