If you would like guests to indicate their ETA when making an online booking, we have a setting for that.
See Reservations > Settings > Booking Configuration.
Watch this quick video to learn how to use the setting.
If you turn on the ETA setting, your guests will see it in the highlighted space below when making a booking online.
The field will show up in the reservation details like so:
As well as on the reservations table:
It will also appear on confirmation emails and statements.