After more than three years of incremental growth, Dayton-based PSA Airlines Inc. is hitting the final stage of its fleet expansion, meaning another 1,000 hires.

The Dayton-based airline has 2,950 employees and 115 jets in its fleet today, as it approaches a new final fleet of 150 aircraft. Once its fleet reaches that number it will employ nearly 3,700 people, almost four times what it did three years ago, Dion Flannery, president of the company, told me. Between new jobs and backfilling positions,…