How many favorite airports are shown on the Apple Watch?

The airports page on the Apple Watch displays the top ten airports in your Favorite Airports list. You can change which airports are displayed and in what order by going to the Favorite Airports page on your iPhone, tapping Edit in the upper-right corner, dragging the airports to where you want them in the list, and tapping Done. The list of airports shown on the Watch will reflect any changes made to the list on your iPhone.