The pilots union of Delta Air Lines Inc. sought to show Friday that flying a commercial plane with the lives of hundreds of passengers at stake is a stressful, time-consuming and heavily regulated job that requires a lot of training and professionalism and — ultimately — good pay.

Union lawyers called several retired Delta pilots to testify before an arbitration panel that will decide whether to allow the nation’s third-largest carrier to void its pilot contract and impose up to $325 million in long-term pay and benefit cuts. The union says it will strike if its contract is thrown out.