Yep, the majority were internals. We usually had 2-3 externals per trip. Oddly, the externals never had a problem. Everyone had some sort of duffel. We even had one kid use his dad's golf bag duffel. That ended up in the "odd luggage dept", it didn't show up on the belt with everything else - had to track it down.

The duffel thing and packing for the plane ride is part of our regular training for our Philmont treks - don't want to follow the "advice"? - don't go...

The whole "planning for group travel" is way different then travelling on your own...

Of course, YMMV!!!