I have flown with polarised lenses and experienced no problems. In fact I preferred it.
The only criteria I use is colour definition. The lense has to allow at least "true colour" sensitivity to ensure that your eye remains sensitive to cockpit warning/caution and advisory lights. Dark helmet visors are specifically designed for this - another good reason for wearing a helmet. I would stay well clear of any colour tinted lense such as most of the Bolle range. I am a fan of the Ray Ban G15 lense which was originally designed with aviation (and colour definition) criteria in mind, although a polarised version is very difficult to find these days.
Besides, I keep wearing the Ray Bans in the hope that Kelly McGillis will cross polarise with me!!
