Based in Boston, Northeast Airlines was purchased by Delta on August 1, 1972. With this merger, Delta served Boston for the first time and has since gone on to be one of the leading carriers in the market, along with American. Northeast was the first carrier to operate the 727-200 in 1967. The 727-200 "Yellowbirds" operated non-stop flights from Miami to Los Angeles. Delta didn't operate 727s until it merged with Northeast and went on to become the world's largest 727 operator.