wow, I remember stuff like this (though not 30's and 40's)

When I was young and traveled, it was before phones became ubiquitous.

I had to take a travel clock with me as an alarm clock. You couldn't trust a hotel alarm clock. So I had small sized clocks to wake up for an interview or a conference or a tour or a return flight.

I just forgot about all of this with smart phones and watches that get you up in the right time zone at the right time.