We did both helicopter glacier tour in Juneau and White Pass Railroad in Skagway. Did not tip on either, and was not expected. The helicopter tour is a once in a lifetime experience. We enjoyed it immensely and should not be missed.
For group stuff we rarely tipped. However, we did the extended glacier hike in Juneau, just my wife and I, and the guide took extra care of my wife while we were ice climbing. She made sure we got the whole experience of glacier hiking, not just wandering around the flats for 10 minutes. She belayed us twice up seracs to get a great view of pools, caves and crevasses.
She really enjoyed her job, knew a lot about the glacier and really made it a memorable experience.
For that kind of one on one personal service, we did tip.
I have to disagree "it was not expected" how do you know???? Anyway- I always tip flights especially ones that include transfers. I feel it is better than a "thank you" for an excellent safe tour. What's a few bucks anyway????