The ultra-long haul flights are an aviation first that CEO Vanessa Hudson said would overcome Australia’s tyranny of distance and deliver the airline an extra $400 million in annual earnings.

The long-awaited direct flights are due to take off by the end of 2027.

TOULOUSE, June 17 — Qantas Airways is set on Wednesday to unveil the first destination for the world’s longest non-stop flights from eastern Australia to London or New York,...