There are many aspects of working on the British Airways flight operations team where basic math concepts are beneficial to success in the role. Mostly in regard to the loading and packing of freight on an aircraft, your interviewer is really trying to gather that you have the ability to make basic math calculations on your feet to prove you'll be successful in this role. Keep in mind that Operations Agents can have varying levels of educational background, from a high school degree to a Bachelor's degree, so be sure to read up on the requirement for this position when you do apply. On top of talking about the highest level of math that you completed, be sure to talk about any jobs you've held where quick math skills were essential.
