Do you remember as a child how you dressed to take trips?
(You can either begin your sermon with an interactive time at this point, inviting the congregation to remember how they were dressed for trips, or you can make it personal and tell your own recollections of what kind of clothes your parents made you wear when it was time to travel.)
As a child I remember having to get dressed up whenever we'd go on a family trip. If we were going in our own car, we could be more casual, but still had to look good enough to go into a restaurant for a meal, or to appear to check in at some overnight establishment (even though these were always cheap, family-friendly motels).
If a bus trip was involved we had to look even nicer, since we'd be traveling with all sorts of other people. Besides, since…