Modern Comics #65 (1947)

In the storm-lashed skies above Thunder Mountain, a series of mysterious plane crashes has terrified pilot Frank Lee and grounded his cargo flights—until Blackhawk arrives to investigate. With Lee determined to prove the route is safe, Blackhawk races to uncover the truth behind the eerie sightings of the Thunder Bird, a phantom creature said to haunt the peaks. As the storm rages and danger mounts, Blackhawk must unravel the mystery before another flight meets its fate.