All motion picture cameras can have this effect on apparent propeller speed. It's caused by the camera frame rate being a near multiple of the prop revolutions per second. At some prop speeds the camera can actually make it look like it's going in reverse.
Not much can be done about it since we can't change the camera frame rate without introducing extra editing headaches. Increasing the exposure time per frame will make the prop blades blur a bit, maybe enough to hide the slow speed appearance. Or you can ask the plane pilot to change his engine rpms.
Fav quote - "Experience is whatcha don't get 'till ya don't need it no more."
System - Athlon 1.4GHz, Win98, Hauppauge PVR250 receiver and compressor.
Software -Magix Movie Edit Pro 10, Nero 6 + NeroVision Express, Moho 4.61, PSP 8.1, Bryce, Quicktime 6.52 pro, Goldwave 5, DVD-Lab.
Cameras - Panasonic GS9, Canon ES8400V, Canon EOS D20 and Canon A70