Airplane maker Airbus  (EADSY) blamed a faulty engine made by United Technologies  (UTX - Get Report) subsidiary Pratt & Whitney for delays in delivering its A320neo passenger jet. 

United Technologies shares were down more than 1% premarket Thursday. 

Airbus finance director Harald Wilhelm said that the delays in deliveries last year were the main reason the company reported a 52% drop in quarterly profits. 

"The demonstrated performance so far is not satisfactory, but let's see whether their fixes are coming through (and) are finally confirmed. ... We still need to see the proof coming through," Wilhelm said, according to Reuters. 

Pratt & Whitney is one of two engine suppliers for the A320neo. Airbus plans to deliver 720 airplanes in 2017.