This sentence is usually used to establish whether you have ever at any point in your past worked for Qatar airways or one of the companies directly associated with it (as in owned by the same company or one of its sister companies).
This is a pretty common question in interviews because it helps establish some known history about the candidate, their motivation for leaving a similar post perhaps, and their likelihood of performing well in a relatively equal position.
So, in brief, if you have worked for Qatar airways or one of it's associated brands - then this is where you would disclose that information!