Apple Calendar Time Zone

I've just given up creating timezoned start and finish times in MacOS Sierra. But in iOS 10 and iOS 11, you can assign a different timezone to start and finish. It turns up correct in my linked iCloud calendar & my OSX calendar the right way, showing the correct duration and all. Time to fix MacOS

In Calendar Advanced Preferences there is an option to turn on Time Zone Support.

This is not a totally satisfactory solution, as the Time Zone applies to the whole event.

When I am flying I enter Departure time in my local Time Zone, and create a separate event for Arrival in the other Time Zone.