Vero Beach, Fla.-based Piper Aircraft said it is delaying first deliveries of the single-engine PiperJet from the fourth quarter of 2012 until the second quarter of 2013. To compensate for the delay, Piper favorably changed contract terms for PiperJet customers, including maintaining the price at $2.19 million and changing the CPI escalator date from Oct. 1, 2007, to the beginning of this month. Meanwhile, flight testing of the proof-of-concept PiperJet continues, and the aircraft has logged more than 230 hours to date. Piper has recently started testing stall speeds and stall handling characteristics with the proof-of-concept airplane.