US regional Pinnacle Airlines posted a $31.5 million net loss in 2011, which ended three months before the carrier filed for bankruptcy.
A $51 million annual interest expense added to a 28.4% jump in operating expenses compared with 2010 results, the airline says. Salaries, Pinnacle's largest expense category, soared 36% from 2010 to 2011.
Operating revenue, meanwhile, increased 20.7%, led by a nearly doubling of revenues by Pinnacle's Mesaba airline division, which primarily operates Bombardier CRJ200s for Delta Air Lines.
On 1 April, Pinnacle filed for bankruptcy protection as its cash reserves declined to perilous levels.
The carrier has received a $74 million debtor-in-possession loan from Delta, and unveiled a restructuring plan that winds down subsidiary Colgan Air's turboprop flying for United Airlines.
Pinnacle plans to reform its business as it exits bankruptcy by focusing on 50-seat regional jet flying for Delta.