MEMPHIS (AP) — Pinnacle Airlines says it's filed for bankruptcy protection in order to deal with its mounting debt and costs.

The Memphis, Tenn.-based airline operates regional flights as Delta Connection, United Express and US Airways Express. It says its current business model isn't sustainable.

Pinnacle Airlines Corp. says it's been hurt by rising costs, limited cash and integration problems. After a review, the company's board decided that reorganization under Chapter 11 was its best option.

The company says it will focus on restructuring its operating agreements with Delta, winding down its operations with United Airlines, cutting labor costs and looking for other ways to cut costs.

Pinnacle also says it's received a commitment for $74.3 million in debtor-in-possession financing from Delta that will allow it to continue operating while it restructures.