I recall departing with LH from JFK and the steward across from my seat (emergency exit) told me that they sometimes taxi for 1-2 hours. One hour is almost normal in the evening at JFK, which is why EWR becomes more interesting for many. Can be quite long coming in as well, especially when TSA didn't clear the plane to deboard. Not unusual to hear "we are number 28 for takeoff". Nice to sit in business on those occasions...