The Treasury Department has reached agreements in principle with the major U.S. airlines for federal aid to pay workers and keep them employed through September. The assistance will be a mix of cash and loans totaling $25 billion, and Treasury’s terms would let the government take a small ownership stake in the leading airlines. The carriers did not want to give up equity, but they had little leverage — their business has collapsed as the COVID-19 pandemic reduces air travel to a trickle. American and Delta will each get more than $5 billion. And they could apply for additional loans from a separate $25 billion pool.