How exactly TPC-C v5 synthetic benchmark transactions related to the Delta Airlines backend transactions? Yes, that's somwewhat toyish 'business application' sketch benchmark. The goal of any benchmark is to be the same for all participants to compare them - staying aside the question what exactly the results tell about one or another particular system.

No company outside of exceptional circumstances will give you their actual data and workloads so some generic data points are useful. It's also pretty obvious that number of transaction Delta is handling is few orders of magnitude less than say Walmart. To me the point that conventional RDBMS can not handle transactional workload of Delta sounds like total BS.