Air Wisconsin Airlines Corp. in Appleton is offering hiring bonuses of $33,000 as it seeks to ramp up its pilot ranks to fulfill new business as a regional carrier for United Airlines.

The airlines, which already flies as a regional American Airlines carrier, expects to hire more than 400 pilots over the next two years with starting pay that has been increased to $35 an hour. The airline also raised its retention bonuses for its current first officers to $20,000, with half payable in May and half…